An air craft has a fuel tank fitted with an internal bladder which is vented to the outside of the fuselage. The vent opening is covered with a small fairing. What has been damaged and blocked?
A) May cause fuel bladder collapse by a decrease in tank pressure
May cause a fuel tank leak by increasing tank pressure
C) May cause excessive fuel flow by increasing fuel pressure

Please anyone with bright explanation

Hard to answer without seeing the whole question yes the tank may expand if the vent is blocked

Yes, the question wording leaves a lot to be assumed. Maybe what they're getting at is this. If the bladder type fuel tank has a blocked vent, then as the fuel is burnt during flight no air can enter to replace it. That causes a partial vacuum to develop in the tank which may eventually lead to the tank collapsing, or possibly an interruption to the fuel supply to the engine (or both).

The wording you have provided makes it impossible to give a clear answer.