In futures trading, the contract size denotes the predetermined quantity of the underlying asset to be delivered or settled for a single futures contract.
For instance, a gold futures contract might stipulate a contract size of 1 kilogram, signifying that one contract corresponds to 1 kg of gold.
Explanation of Other Options:
(A) Basis: The disparity between an asset's spot price and its futures price.
(B) Contract cycle: The duration or months within which futures contracts reach expiration.
(D) Expiry date: The specific date on which a futures contract becomes void.
Consequently, option (C) accurately specifies the quantity of an asset per futures contract.