Cell-mediated immune responses protect against

Cell-mediated immune responses protect against
  a. viruses.
  b. bacteria.
  c. fungi.
  d. cancer cells.
  e. all of these

Question 2

The infinite variety of antibodies that can be generated by B cells is due to
  a. the infinite variety of genes in these cells.
  b. the shuffling of genes to produce an infinite variety of proteins.
  c. the recombination of genes due to crossing over.
  d. the infinite variety of genes in these cells and the recombination of genes due to crossing
  over.
  e. the infinite variety of genes in these cells, the recombination of genes due to crossing over,
  and the shuffling of genes to produce an infinite variety of proteins.