Explanation/Reference:
This question is testing your ability to evaluate whether items on the list are Qualitative or Quantitative. All of the items listed were Qualitative except Lost of Revenue which is Quantitative.
Those are mainly two approaches to risk analysis, see a description of each below:
A quantitative risk analysis is used to assign monetary and numeric values to all elements of the risk analysis process. Each element within the analysis (asset value, threat frequency, severity of vulnerability, impact damage, safeguard costs, safeguard effectiveness, uncertainty, and probability items) is quantified and entered into equations to determine total and residual risks. It is more of a scientific or mathematical approach to risk analysis compared to qualitative.
A qualitative risk analysis uses a "softer" approach to the data elements of a risk analysis . It does not quantify that data, which means that it does not assign numeric values to the data so that they can be used in equations.
Qualitative and quantitative impact information should be gathered and then properly analyzed and interpreted. The goal is to see exactly how a business will be affected by different threats.
The effects can be economical, operational, or both. Upon completion of the data analysis, it should be reviewed with the most knowledgeable people within the company to ensure that the findings are appropriate and that it describes the real risks and impacts the organization faces. This will help flush out any additional data points not originally obtained and will give a fuller understanding of all the possible business impacts.
Loss criteria must be applied to the individual threats that were identified. The criteria may include the following:
Loss in reputation and public confidence
Loss of competitive advantages
Increase in operational expenses
Violations of contract agreements
Violations of legal and regulatory requirements
Delayed income costs
Loss in revenue
Loss in productivity
Reference used for this question:
Harris, Shon (2012-10-18). CISSP All-in-One Exam Guide, 6th Edition (p. 909). McGraw-Hill. Kindle Edition.

Explanation/Reference:
A Public Key is also known as an asymmetric algorithm and the use of a secret key would be a symmetric algorithm.
The following answers are incorrect:
Use of the recipient's public key for encryption and decryption based on the recipient's private key. Is incorrect this would be known as an asymmetric algorithm.
Use of software encryption assisted by a hardware encryption accelerator. This is incorrect, it is a distractor.
Use of Elliptic Curve Encryption. Is incorrect this would use an asymmetric algorithm.

Since the circuit level proxy does not anayze the application content of the packet in making its decisions, it has lower overhead than an application level proxy.
"More difficult to maintain" is incorrect. Circuit level proxies are typicall easier to configure and simpler to maintain that an application level proxy.
"More secure" is incorrect. A circuit level proxy is not necessarily more secure than an application layer proxy.
"Slower" is incorrect. Because it is lower in overhead, a circuit level proxy is typically faster than an application level proxy.
References: CBK,pp. 466 - 467 AIO3, pp.488 - 490

Both are the components of a sensitivity label.
The following are incorrect:
A Classification Set and a single Compartment. Is incorrect because the nomenclature "Classification Set" is incorrect, there only one classifcation and it is not a "single compartment" but a Compartment Set.
A single classification and a single compartment. Is incorrect because while there only is one classifcation, it is not a "single compartment" but a Compartment Set.
A Classification Set and user credentials. Is incorrect because the nomenclature "Classification Set" is incorrect, there only one classifcation and it is not "user credential" but a Compartment Set. The user would have their own sensitivity label.