in T flip flop if the input value is low (0) it remains in the previous state but if the input value is high(1) it basically changes the state (Toggle/complement)
characteristic table of T flip flop:
$T$ |
$Q_n$ |
$Q_{n+1}$ |
$0$ |
$0$ |
$0$ |
$0$ |
$1$ |
$1$ |
$1$ |
$0$ |
$1$ |
$1$ |
$1$ |
$0$ |
From the above table $Q_{n+1}=\bar TQ_n+T\bar Q_n$
or $Q_{n+1}=T\oplus Q_n$
Option $(A)$ is correct here.