Which of the Following Best Describes the Role of Regulatory

Which of the following best describes the role of regulatory T cells?

A) Regulatory T cells are a kind of helper T cell that stimulates B cells.
B) Regulatory T cells are a kind of helper T cell that stimulates cytotoxic T cells.
C) Regulatory T cells help limit the immune system response.
D) Regulatory T cells stabilize and support memory cells.
E) Regulatory T cells stimulate natural killer cells to attack tumors.