Answer:
Option C is the correct answer.
Explanation:
The equation is given as :

Solving this by pairing the like terms together,


This gives

Now, we will solve all the equations to check which is same as the above.
A.

=>

=>

=>

This is the wrong option.
B.

=>

=>

=>

=>

=>

This is the wrong option.
C.

=>

=>

=>

This is the right option.
D.

=>

=>

=>

=>

Dividing by 7, we get
=>

This is the wrong option.
Therefore, option C is the correct answer.