Ithink 40 is the answer but i need confirmation

I'd say we can't tell from the information given in the picture. We don't know what's on the right side of the right pulley.

If the rope that goes under the right pulley goes up the right side of it to, say, another hook in the ceiling, then there are two ropes holding the right pulley and the 40N weight. The tension on each side of the right pulley is 20N, and W is 20N.

But we don't know ... we can't see what happens to the rope when it goes under the right pulley.

The correct answer is: a