The correct answer is C. Wasteful.
Expensive is not a synonym of extravagant because expensive can refer to something that costs a lot of money, while extravagant can refer to something that is wasteful or excessive. Proud is not a synonym of extravagant because proud refers to someone who has a high opinion of themselves, while extravagant does not necessarily have anything to do with someone’s opinion of themselves. Reckless is not a synonym of extravagant because reckless refers to someone who takes unnecessary risks, while extravagant does not necessarily have anything to do with taking risks.
Wasteful is a synonym of extravagant because both wasteful and extravagant refer to something that is excessive or unnecessary. For example, if someone buys a new car every year, they could be considered wasteful or extravagant.