Explanation
When the economy is expanding, firms are less likely to default. Therefore the conditional probability of default, given an economic expansion, is likely to be lower than the unconditional probability of default.
Therefore Choice 'a' is the correct answerand the other statements are incorrect.

Explanation
Model risk is the risk that a model built for estimating a variable will produce erroneous estimates. Model risk is caused by a number of factors, including:
a) Misspecifying the model: For example, using a normal distribution when it is not justified.
b) Model misuse: For example, using a model built to estimate bond prices to estimate equity prices c) Parameter estimation errors: In particular, parameters that are subjectively determined can be subject to significant parameter estimation errors d) Programming errors: Errors in coding the model as part of computer implementation may not be detected by end users e) Data errors: Errors in data used for building the model may also introduce model risk Therefore the correct answer is d, as all the choices are a source of model risk.

Explanation
When a derivative position is entered into, its mark-to-market value is generally close to zero (though the notional may be high). With the passage of time, the derivative's value fluctuates in an unpredictable way, creating a counterparty exposure that may be difficult to estimate and risk manage. Counterparty risk in such cases is estimated based on Potential Future Exposure, which may be calculated using either:
a) Take the mark-to-market at present, and add a certain percentage of the notional, or b) Perform a Monte Carlo simulation, capturing the stochastic nature of the PFE.
Therefore I and II are valid choices. MLE and parametric estimation are not methods for calculating PFE.

Explanation
Top down approaches do not consider event frequency and severity, on the otherhand they focus on high level available data such as total capital, income volatility, peer group information on risk capital etc. Bottom up approaches focus on severity and frequency distributions for events. Statement I is therefore not correct.
Top downapproaches do indeed rely upon high level aggregate data and tend to infer operational risk capital requirements from these. Bottom up approaches look at more detailed firm specific information. Statement II is correct.
Scenario analysis requires estimating losses from risk scenarios, and allows incorporating the judgment and views of managers in addition to any data that might be available from internal or external loss databases.
Statement III is correct. Therefore Choice 'b' is the correct answer.

Explanation
According to Basel II, in any given year, negative capital charges(resulting from negative gross income) in any business line may offset positive capital charges in other business lines without limit. Therefore Choice 'b' is the correct answer.