Concept:Rewrite the integrand in terms of tanx and use substitution t=tanx.Explanation:LetI=∫sec2/3x⋅csc4/3xdxRewrite asI=∫sin4/3xcos2/3xdxUsing sinx=tanxcosx,I=∫tan4/3x⋅cos2xdxSo,I=∫tan4/3xsec2xdxPut tanx=t, so sec2xdx=dt.I=∫t−4/3dt=−1/3t−1/3+cI=−3tan−1/3x+cAnswer:−3tan−1/3x+cHence, the correct option is B.