Final answer:
According to Denise Kandel, family and peers are the socialization agents most closely related to an individual's drug use. These groups are influential in shaping behaviors and norms that can either deter or promote drug usage. Option a.
Step-by-step explanation:
According to Denise Kandel's research, the socialization agents that are tightly related to drug use are family and peers. These agents of socialization, which include close social groups such as family members and friends, substantially influence the behaviors and norms of individuals, including drug usage patterns. Family can either instill values and norms that deter drug use or, conversely, expose an individual to such behavior. Likewise, peer groups play a crucial role during adolescence as they can heavily influence an individual's decision to use drugs through peer pressure and the desire for social acceptance.
Additionally, while not directly mentioned by Denise Kandel, it is important to recognize that other agents such as schools, workplaces, religious institutions, and the media also contribute to the socialization process by communicating and reinforcing cultural norms and values, but the most direct impact regarding drug use usually stems from family influence and peer relationships.