The Application Layer determines the identity of the communication partners and
this is where Non-Repudiation service would be provided as well. See the layers below:
DOD Model DoD Model
The following answers are incorrect:
network layer. Is incorrect because the Network Layer mostly has routing protocols, ICMP, IP, and
IPSEC. It it not a layer in the DoD Model. It is called the Internet Layer within the DoD model.
transport layer. Is incorrect because the Transport layer provides transparent transfer of data
between end users. This is called Host-to-Host on the DoD model but sometimes some books will
call it Transport as well on the DoD model.
data link layer. Is incorrect because the Data Link Layer defines the protocols that computers must
follow to access the network for transmitting and receiving messages. It is part of the OSI Model.
This does not exist on the DoD model, it is called the Link Layer on the DoD model.

A project management tool that can be used to plan, execute, and control a
software development project is the systems development life cycle (SDLC). The SDLC is a
process that includes systems analysts, software engineers, programmers, and end users in the
project design and development.
Because there is no industry-wide SDLC, an organization can use any one, or a combination of
SDLC methods.
The SDLC simply provides a framework for the phases of a software development project from
defining the functional requirements to implementation. Regardless of the method used, the SDLC
outlines the essential phases, which can be shown together or as separate elements.
The model chosen should be based on the project. For example, some models work better with
long-term, complex projects, while others are more suited for short-term projects. The key element
is that a formalized SDLC is utilized.
The number of phases can range from three basic phases (concept, design, and implement) on
up.
The basic phases of SDLC are:
Project initiation and planning
Functional requirements definition
System design specifications
Development and implementation
Documentation and common program controls
Testing and evaluation control, (certification and accreditation)
Transition to production (implementation)
The system life cycle (SLC) extends beyond the SDLC to include two additional phases:
Operations and maintenance support (post-installation)
Revisions and system replacement
The following answers are incorrect:
Functional Requirements Phase
Acceptance Phase
Postinstallation Phase
The following reference(s) were/was used to create this question:
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition
((ISC)2 Press) (Kindle Locations 11790-11809). Auerbach Publications. Kindle Edition.

Answer "Objects never change their security level in a way that would violate the system security policy" is known as the weak tranquility property. The two other answers are distracters.

OSI model needs to know the source of the data and that it is who it says it is. Path it the data take is not cared about unless source routing is used. The level of security is not cared about inherently by the receiving node (in general) unless configured. A is the best option in this question.

Explanation
Section: Security Operations