ANSWER: Marketing because it is simply advertising
EXPLANATION: photographer who is taking pictures for the advert purpose of a brand is actively involved in the Marketing career path of the company he works with. this is because advertising(marketing communication) is part of a long chain of marketing techniques used by the company to promote their products and also to get returning and new customers patronizing them much more.
marketing communication is embedded into marketing which is the main career. although what the photographer is doing is part of the marketing communications but the career pathway of which he is involved with is the MARKETING career.