**Correct option (C) 4 sec**

**Explanation:**

At t = 2 sec, u = 10 × 2 = 20m/s

After t = 2sec

v = u + at

0 = 20 – 10t

t = 2 sec.

Hence, at t = 4 sec. the particle is at its farthest distance from the y-axis.

The particle is at farthest distance from y-axis at t ≥ 4. Hence the available correct choice is t = 4.