A. When returns data cannot be analytically modeled
B. When returns are discontinuous or display large jumps
C. Where analytical methods are too complex to effectively use
D. All of the above
Explanation:
Monte Carlo simulations can be effectively used in all cases where an analytical estimate of the VaR cannot be made for any reason - which may include complexity of portfolios, discontinuities or non-linearity in returns or just the plain unavailability of closed form analytical models. Therefore Choice 'd' is the correct answer.