An apple costs Rs. 10. An onion costs Rs. 8. Select the most suitable sentence with respect to grammar and usage. A. The price of an apple is greater than an onion. B. The price of an apple is more than onion. C. The price of an apple is greater than that of an onion. D. Apples are more costlier than onions.

GATE 2016 · General Aptitude · Comparative Forms · medium

Answer: C. The price of an apple is greater than that of an onion.

1. Eliminate options with illogical comparisons: Option A: 'price of apple > an onion' compares a price to a fruit — illogical. Option B: 'price of apple > onion' has the same flaw and also drops the article. Both are eliminated.
2. Eliminate Option D for double comparative error: 'More costlier' is a double comparative — 'more' and '-er' cannot be used together. 'Costlier' or 'more costly' would each be correct alone, but not combined.
3. Confirm Option C: Option C: 'The price of an apple is greater than that of an onion.' Here 'that of an onion' = 'the price of an onion', making it a logical price-to-price comparison with correct grammar.