Answer:
10.8 amu
Explanation:
11 * 0.80 = 8.8 (11 represents ion, 0.80 represents %)
10 * 0.20 = 2 (10 represents ion, 0.20 represents %)
8.8 + 2 = 10.8 amu
but i think it's C
A. Student A because it requires a hypothesis