C is the correct answer. Opposites attract!
Answer:
They oscillates perpendicularly to one another, the oscillation of one field generates the other field.
Explanation:
In a light wave, an oscillating electric field of a light wave produces a magnetic field, and the magnetic field also oscillates to produce an electric field. The magnetic field and the electric field of a light wave both oscillates perpendicularly to one another. The resultant energy and direction of the wave generated as a result of these oscillating fields is propagated perpendicularly to both fields.
Which one if you want independent variable meaning that means variable (often denoted by x ) whose variation does not depend on that of another.
Before getting an answer for it first we have to understand nuclear fusion.
Nuclear fusion is a thermo-nuclear reaction in which two light unstable nuclei will form a heavy stable nuclei. In this process there will be some mass defect which will be converted into energy as per Einstein's mass energy equivalence theorem.
The theorem is stated as
where c is the velocity of light and m is the mass converted into energy.
One take an example of fusion in sun where 4 hydrogen atoms combine to form a helium nucleus which are explained below-



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Here
is the positron.
In this process very high temperature is needed which is approximately equal to the temperature of the sun i.e 
Such temperature is very difficult to initiate the reaction on the earth surface. It should be carried out in an sustainable way also .Otherwise It will cause nuclear hazards.