Bits $1$ and $0$ are transmitted with equal probability. At the receiver, the pdf of the respective received

signals for both bits are as shown below.

If the detection threshold is $1,$ the $BER$ will be

- $\frac{1}{2} \\ $
- $\frac{1}{4} \\$
- $\frac{1}{8} \\$
- $\frac{1}{16}$