Explanation
The correct answer is choice 'a'
A long position in a credit sensitive bond is equivalent to earning the risk free rate and the spread on the bond.
The risk free rate can be earned through a long position in a treasury bond, and the spread can be earned in the form of premiums on a CDS, which are received by the protection seller, ie the party short a CDS contract.
Therefore we can get the same results as a long bond position using a combination of a long treasury bond and a short position in a CDS. Choice 'a' is the correct answer.

Explanation
CreditRisk+ treats default as a binary event, ignoring downgrade risk, capital structures of individual firms in the portfolio or the causes of default. It uses a single parameter, or the mean default rate, and derives credit risk based upon the Poisson distribution. Therefore Choice 'c' is the correct answer.

Explanation
The index option is affected by the spot value for the underlying index, as also the risk free interest rate, or the zero rate for the duration of the option. It is also affected by the volatility of the underlying. The 'strike price' is set and is fixed at the time the option is purchased, and therefore is not a risk factor.
Therefore other than IV, all other choices are valid risk factors that underlie an equity index option.
Other instruments may have other risk factors - for example, a long forex position will have the spot exchange rate as the only risk factor.

Explanation
When assets are uncorrelated, variances are additive. But volatility (which is standard deviation) is not. In the given situation, the total variance of the portfolio will be equal to the the square root of the sum of the variances of the assets in the portfolio weighted by the square of their weights. Its volatility will be the square root of this variance. Thus Choice 'c' is the correct answer.
(This is because V(cA + dB) = c^2 V(A) + d^2 V(B) - refer tutorial on combining variances.) Choice 'd' is incorrect as it describes the calculation of variance, not volatility. Also, the presence of a large number of uncorrelated assets does not create a portfolio with volatility equal to zero or that of the market. The other choices are therefore incorrect.

Explanation
All of the listed reports (or information) would be useful to a risk manager analyzing liquidity risk. Therefore Choice 'c' is the correct answer. Additionally, reports on assets brought on margin (that may result in collateral or margin calls), trading exposures to different counterparties, reports on financial health, share price and credit ratings of key counterparties will also be useful.