Select the sentence that is grammatically correct:

The correct answer is Option (3) → At present the flat above ours belongs to my aunt, but she is selling it to a family from Indore.

Verbs of state are not used in the continuous:

• Some verbs show a state, not an action. Examples are belong, own, know and contain.
• These verbs are not used in the -ing form, even with “at present”. So the flat belongs to my aunt, not “is belonging”.
• “Is selling” is correct. Selling is an action, and it is already going on.

Why the Other Options are Incorrect?

Option 1: The new furnitures for our staff room arrived from the carpenter’s workshop on Monday. — Incorrect. “Furniture” has no plural form, so it never takes an “-s”.
Corrected: The new furniture for our staff room arrived from the carpenter’s workshop on Monday.

Option 2: You had better to leave now if you want to catch the last bus to Thane. — Incorrect. “Had better” is followed by the base form of the verb, without “to”.
Corrected: You had better leave now if you want to catch the last bus to Thane.

Option 4: The kadhi simmering on Dadi’s stove smells nicely, so everyone has gathered in the kitchen. — Incorrect. After “smell”, we use an adjective that describes the food, not an adverb.
Corrected: The kadhi simmering on Dadi’s stove smells nice, so everyone has gathered in the kitchen.