Which of the following improper integrals is (are) convergent?

GATE · 1993 · CS · Question 1 subparts

1. A.

   ∫₀¹ sin x/(1 − cos x) dx

2. B.

   ∫₀∞ cos x/(1 + x) dx

3. C.

   ∫₀∞ x/(1 + x²) dx

4. D.

   ∫₀¹ (1 − cos x)/(x⁵/2) dx

Attempted by 2 students.