Geographical classification of mountains is a frequent exam topic. The Vosges mountains are structurally block mountains formed by faulting and crustal uplift associated with rifting in Western Europe. They are the twin of the Black Forest range. Fold mountains, like the Alps, are formed by the buckling of crustal layers, which is not the case for the Vosges. Statement A is correct (Sierra Nevada is a massive block), B is correct (Monadnock is the namesake for isolated residual hills) and C is correct (Kilimanjaro is Africa’s most famous volcanic peak). Therefore, pair D is the incorrect match.