Curious Carl and his lab partner added small pieces of various metals to HCl. Magnesium (Mg) and zinc (Zn) reacted vigorously with HCl, releasing hydrogen gas. This equation represents the reaction of zinc in hydrochloric acid.

Zn + 2HCl → ZnCl2 + H2
What is the half reaction for the reduction of hydrogen in the reaction?

A) 2HCl → + 2e- + H2(g)
B) H + Cl → + 2e- + H2(g)
C) 2H+ + 2e- → H2(g)
D) 2H+ - 2e- → H2(g)