Where sales are £87,000, fixed costs £21,000 and the profit £8,000, the variable cost and the contribution should be:

Variable Cost | Contribution
A) 58,000 | 29,000
B) 29,000 | 58,000
C) 79,000 | 66,000
D) 66,000 | 79,000

An explanation would also be helpful so I can understand why.. Thanks!

Profit = Sales - Variable Costs - Fixed Costs

Plug your three knowns into that one, and solve for the unknown.

Then, Contribution = Sales - Variable Costs

(Although frankly, once you've got the first one, you've automatically got the second one. Poor question design, unless they just wanted the second one to serve as a corroborating check that you've answered with the right choice.)