Answer:
ummm I think the answer is Carrot
use unitary method
for 5 it costs 330p
so for 1 choc it will cost 330/5
to get 9,
(330/5) =66
66 multiplied by 9 =594
therefore 9 will cost 594p
The equation is a scientific law, Newton's Law of Gravity,

This is a pretty bad question. Newton's Law of Gravity is a mathematical model of gravitation, originally a theory, verified by observation, and now superseded by the General Theory of Relativity.
C is probably the best answer to this poor question.
X=-4-y there you go enjoy