When a telemarketer calls to sell a consumer life insurance, the last questions asked is what category does the person's household income fall into (less than $50,000; $50,000 to $99,999; and $100,000 and over). When the telemarketer asks about household income, this indicates the use of which type of consumer variable the firm is using to segment its market?a. usageb. behaviorc. demographicd. buying situatione. psychographic