According to Fourier’s law, amount of heat flow (Q) through the body in unit time is equal to

A

$$ KA \frac {dT}{dx} $$

B

$$ KA \frac {dT^2}{dx^2} $$

C

$$ K \frac {dx}{dT} $$

D

$$ KA \frac {dx}{dT} $$