The common difference of the A.P. is 12q, 1 - 2q2q, 1 - 4q2q, . . . . is

Answer: Option A

$$\begin{array}{rl}& \text{A}\text{.P}\text{.}\text{is}\frac{1}{2q},\frac{1-2q}{2q},\frac{1-4q}{2q},....\\ & \Rightarrow \frac{1}{2q},\left(\frac{1}{2q}-1\right),\left(\frac{1}{2q}-2\right),....\\ & \text{Clearly}d=\left(\frac{1}{2q}-1\right)-\frac{1}{2q}\\ & =\frac{1}{2q}-1-\frac{1}{2q}\\ & =-1\end{array}$$