According to Boyle's law for a perfect gas

A

$$\frac{T_2}{T_1} = \frac{P_2}{P_1}$$, if V is kept constant

B

$$\frac{T_2}{T_1} = \frac{V_2}{V_1}$$, if P is kept constant

C

$$\frac{P_1}{P_2} = \frac{V_2}{V_1}$$, if T is kept constant

D

None of these