Ask
The lowest price a seller is willing to accept for an option contract.
Explanation
The ask price represents the minimum price at which a market participant is willing to sell. Together with the bid, it forms the bid-ask spread, which is a key measure of liquidity. Tighter spreads generally indicate more liquid markets.
Example
If the ask for a call option is $2.50, you would need to pay at least $2.50 per share ($250 per contract) to buy it.