Which of the following statements is correct regarding antibodies?

• A
  $B$-cells help $T$-cells in antibody production.
• B
  $T$-cells help $B$-cells in antibody production.
• C
  $B$ and $T$-cells help each other in antibody production.
• D
  $B$ and $T$-cells produce antibodies independently without each other's help.