Correct answer is (B).

Let’s say that the tension in string connecting $B$ and $C$ is $T_1$ and that in the string connecting $A$ and $B$ is $T_2$

and let’s say that $B$ and $C$ are moving downwards with an acceleration $a$,

Then writing newton’s 2nd law for $A$, $B$ and $C$ we get the following 3 equations in 3 unknowns ($T_1$, $T_2$ and $a$)

$A$: $T_2 – 2g = 2a$

$B$: $T_1 + 2g – T_2 = 2a$

$C$: $2g – T_1 = 2a$

Solving the 3 equations we will get $T_1 = 13.3$ N.

Very nice questions thanks you sir it’s really help me for practice on this topic