25. Complete the following nuclear reaction equation by filling in the "?" with a particle that balances the equation.

14 6C = 14 7N +?
A. 0 +1e
B. 4 2He
C. 0 -1e
D. 1 0n

B. 4 2He

To balance the nuclear reaction equation, you need to make sure the atomic numbers and the mass numbers balance on both sides of the equation.

Looking at the original equation:
14 6C = 14 7N + ?

The atomic number on the left side is 6 (carbon), and on the right side, it is 7 (nitrogen). To balance the atomic numbers, we need to add a particle with an atomic number of 1.

Looking at the answer choices, we have:
A. 0 +1e (no atomic number of 1)
B. 4 2He (atomic number of 2, not 1)
C. 0 -1e (no atomic number of 1)
D. 1 0n (atomic number of 0, not 1)

The correct answer is B. 4 2He, as it has an atomic number of 2, which balances the equation.