Answer: A.) Expertise
Explanation: The endorsement usually offered by doctors during advert placement on products in the hygiene category such as soap, toothpaste and sanitary products is used to denote expertise. Doctors are well known and highly revered in areas of medicine including hygiene and health, there endorsement of such products is much likely to lead to higher approval rate among consumers and thus success of the product than endorsement offered by non-health or hygiene professional such as a banker.