Answer : Option A

Explanation :

The reason for the shock and disbelief among the scientists is their belief that nothing can travel faster than light. Hence, (A) is an assumption.

Since it is proved twice that there are particles which travel faster than light, the scientists may check the correctness of the long held Einstein's theory that nothing can travel faster than light. Hence, (B) is a possible effect.

It is said that the test would be conducted some more times to confirm the result. From this it can be inderstood that result from one experiment cannot be taken as conclusive evidence. Hence, (C) is an inference.

There is no information weather the first experiment is conducted properly or not. Hence, it can neither be concluded nor is an assumption that there was an error in the first experiment. Hence, (D) is out of context.

It is not clear whather the experiment is done with the intention of finding the speed of neutrinos or it is an accidental discovery. Hence, (E) is out of context.

Statement (A) is an assumption.