**Options**

- 90cm
- 135cm
- 180cm
- 225cm

**The correct answer is C.**

**Explanation:**

d α t^{2 }d = t^{2} k

where k is a constant. d = 45cm, when t = 3s; thus 45 = 3^{2} x t

k = = 5

thus equation connecting d and t is d = 5t^{2 }when t = 6s, d = 5 x 6^{2}

= 5 x 36

= 180cm