A
Only one
B
Only two
C
Only three
D
All four
Correct answer: (b) Only two
Explanation
- A
Only one
Only one. Two rows are correctly typed.
- B
Only two
Only two. Appalachians and Andes are fold mountains. Vosges are block, not fold; Alps are fold, not block.
- C
Only three
Only three. The first two rows are swapped types.
- D
All four
All four. Vosges and Alps are mis-typed.
Summary. Official key is (b) only two. Vosges (Central Europe / west of the Rhine) are block (fault-block) mountains, not fold. The Alps are fold mountains, not block. The Appalachians and the Andes are fold mountains. So rows 3 and 4 match; 1 and 2 do not.
Same topic · past papers
UPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.