The correct option is A a tautology
The truth table of given expression is given below
pqx≡p→q∼p∼p→qy≡(∼p→q)→qx→yTTTFTTTTFFFTFTFTTTTTTFFTTFTT
For all possible truth values of p and q, the statement (p→q)→((∼p→q)→q) is true.
Hence, the given statement is a tautology.