Option: B is the correct answer.
B. A biconditional is only true if both statements have the same truth value.
Biconditional statement--
A statement is said to be a biconditional statement if it is given in the form:
p if and only if q
where p is the hypotheses and q is the conclusion of the statement.
Also, the statement is true only if both the statements have the same truth values otherwise it is false.