Part 1. Suppose you were studying some antigen presenting cells that always have MHC Class I on their membrane, but, no matter how you activated the cells, they never expressed MHC Class II on their membrane. (note: MHC can only be expressed on the membrane if it is loaded with a peptide) Question 1: Which of the following defects might explain the situation described * above? A. There is no TAP1 or TAP2 in the cell B. Endogenous peptides are not processed properly C. There are too many exogenous peptides outside the cell D. There is no invariant chain in the cell E. Proteins aren't getting digested in the lysosome. Question 2: In 1-2 sentences, convince me your answer to Question 1 is correct. * Your answer.