The correct answer is D.

Multifactor models are an extension of single-factor models (like the CAPM) and use multiple factors to explain asset returns. Therefore, they inherently take into consideration multiple risk factors (Option A) and contain multiple betas corresponding to the sensitivities to each of these factors (Option C). Additionally, these models generally assume that portfolios are well-diversified, meaning that idiosyncratic (firm-specific) risk is diversified away and only systematic risk factors affect the expected returns (Option B). Thus, all of the given statements are correct.