Is the equation correctly balanced? Yes it is.
The mol ratio is the number in front of one chemical to the other.
There is a 3 in front of the Fe.
There is a 1 in front of the Fe3O4
Edit
What the original answer gave was the mole ratio of Fe to Fe3O4. It is actually the other way around. The answer should be 1:3 because it was asked as Fe3O4 to Fe.
The correct answer is A <<<<<<<< Correct Answer.
