I think it may be c, 1.7 v. I work with electricity a lot.
Answer:
Induced emf through a loop of wire is 3.5 V.
Explanation:
It is given that,
Initial magnetic flux, 
Final magnetic flux, 
The magnetic flux through a loop of wire decreases in a time of 0.4 s, t = 0.4 s
We need to find the average value of the induced emf. It is equivalent to the rate of change of magnetic flux i.e.



So, the value of the induced emf through a loop of wire is 3.5 V.
If one body is positive, and the other is negative, they tend to attract!
The energy that was once potential is now kinetic and the amour of energy is the same