Concept:Use the identities sec2θ−1=tan2θ and csc2θ−1=cot2θ.Explanation:Let α=sec−14, so secα=4.Let β=csc−13, so cscβ=3.The given expression becomes tan2α+cot2β.Now, tan2α=sec2α−1=42−1=15.Also, cot2β=csc2β−1=32−1=8.Therefore, tan2α+cot2β=15+8=23.Answer:23, which is option C.