Final answer:
Uniqueness is not a factor that typically explains initial attraction; familiarity, proximity, and misattribution of arousal are common factors that influence the formation of initial relationships.
Step-by-step explanation:
All the following explain initial attraction to others, except d) Uniqueness. The factors that lead to initial attraction commonly include a) Familiarity, as repeated encounters with a person can increase our liking for them.
Another key factor is c) Proximity, as being physically near someone gives us more opportunities to form connections. b) Misattribution of arousal can also play a role, where the physiological arousal due to one cause can be misinterpreted as attraction to a person present. Uniqueness, however, does not generally explain initial attraction; while it can contribute to long-term interest, it's not typically a primary factor in initiating relationships.