Both of the answers above already got E, and they're right, but I think this question is worth slowing down on, because the trap is subtle in a specific way.
Set it up: Steven's raw increase each year is some fixed amount, call it d. Stuart's increase in year 2 is T0(1+r)r, where T0 is his starting salary and r is his fixed growth rate. The question stem gives you one equation connecting them: d equals T0(1+r)r. That's the only bridge between the two people, and neither statement touches it directly.
1. Statement 1 says Steven's salary after 2 years was 20 percent more than his starting salary. So S0 + 2d = 1.2 S0, which gives d = 0.1 S0, or S0 = 10d. Now you know Steven's starting salary in terms of d. You know nothing about Stuart. Not sufficient.
2. Statement 2 says Stuart's year-2 increase was 11 percent of his starting salary. So T0(1+r)r = 0.11 T0, which simplifies to (1+r)r = 0.11, giving r = 0.1. Notice T0 cancels out completely, so you get Stuart's growth rate but never his salary. Not sufficient.
3. Combine them. Now S0 = 10d, and from the stem equation, T0 = d divided by 0.11. So S0 minus T0 works out to d times 10/11. That's a clean relationship, but d itself was never pinned to an actual dollar figure anywhere in the problem, and every number in this question is a percentage. Scale every salary by any constant and both statements still hold. E.
One-line takeaway: when a DS question is built entirely out of percentages with no dollar figure anywhere, check whether you actually have a value or just a relationship between values.