Hi there! The answer is D.
2x - 1 < 10
2x < 11
x < 5.5
The only set of solutions that make the inequality true is {2, 3, 4}, because filling in this values gives:
2 × 2 - 1 < 10
4 - 1 < 10
3 < 10
2 × 3 - 1 < 10
6 - 1 < 10
5 < 10
2 × 4 - 1 < 10
8 - 1 < 10
7 < 10