Correct option is D
The correct substitution of the highlighted words is (d) their skilful antics.
Explanation: They’re is a contraction of “they are,” which is grammatically wrong before a noun. We need the possessive determiner their to show ownership of the noun phrase skilful antics.
Option (b) there indicates place/existence and does not show possession.
Option (c) dare is a verb/noun unrelated to possession.
Hence, their skilful antics correctly expresses that the antics belong to them.
Also, display is a transitive verb and needs a proper object, which the noun phrase their skilful antics supplies.
Grammatical rule used: Use possessive determiners (my, your, their, his, her, our, its) before nouns to show ownership.
Contractions like they’re (= they are) cannot function as determiners; there functions as an adverb or introductory/expletive there.
Example: They’re happy today. / Put the boxes there. / Their performance impressed everyone.