If printed signs ‘+’ and ‘—’ and numbers 4 and 8 are interchanged. Which one of the following alternatives is correct ?

The equation $4+8+12=16$ becomes $8+4-12=16$. Simplifying the equation, we get $16-12=4$. This is not equal to $16$, so (b) is not the correct answer.

The equation $8-4+12=8$ becomes $4-8+12=8$. Simplifying the equation, we get $8-8+12=12$. This is equal to $8$, so (c) is the correct answer.

The equation $8+4-12=24$ becomes $4+8-12=24$. Simplifying the equation, we get $12-12=0$. This is not equal to $24$, so (d) is not the correct answer.