Which of the following is/are present in a reagent bottle labeled 1.0 M H2SO4?

Question

I. H2SO4
II. HSO4-
III. SO4-2

A. I only
B. I and II
C. II and III
D. I, II, and III

Answer 1

All are present.

Answer 2

apparently the answer is C, yet i cannot find any explanation to it...