Answer:
Option 2nd is correct
the solution set of the given equation is, {0}
Explanation:
Given the equation:

Like terms are those terms which have same variable to the same power.
Combine like terms;

Add 8m both sides we have;

Subtract 14 from both sides we have;

Divide both sides by 16 we have;
m = 0
Therefore, the solution set of the given equation is, {0}