Which among the following sentences uses adjective with correct degree of comparison.

Correct option is D

Option (d) is the only sentence with the correct comparative structure: adjective-er + than (“hotter than”).
Explanation: For one-syllable adjectives like hot, we form the comparative by adding -er (→ hotter) and compare using than. We must not use more with an -er comparative (that would be a double comparative) and we never use to after a comparative of inequality.
Grammatical rule used:
· Comparative (short adjectives): Adj + -er + than (taller than, colder than, hotter than).
· Avoid double comparatives (more hotter, more better ✗).
· Use than, not to, for comparisons of inequality.
Example: Jaipur is cooler than New Delhi in winter.
Errors in other options:
· (a) more hotter to — double comparative ( more + hotter) and wrong preposition ( to).
· (b) more hotter than — double comparative.
· (c) hotter to — wrong preposition ( to instead of than).
Information booster: With longer adjectives (e.g., beautiful), use more + adjective + than (more beautiful than), but never combine more with -er.