Answer: the sensitivity of an option's price to changes in volatility.
Step-by-step explanation:
Vega us defined as the sensitivity of an option's price to changes in volatility. Vega denotes the amount by which the contract's price of an option changes due to the 1% change that occurs in the underlying asset's implied volatility.
Therefore, based on the scenario that has been explained above, the correct answer is the first option above.