Final answer:
Rational Choice Theory is the micro-sociological perspective that suggests individuals aim to maximize gain and minimize cost in their behaviors and interactions.
Step-by-step explanation:
In the field of sociology, the theoretical perspective that is considered micro-sociological and emphasizes that individual behaviors and interactions aim to maximize personal gain while minimizing personal cost is A) Rational Choice Theory. This theory operates on a micro level, similar to B) Symbolic Interactionism, yet it's specifically about the calculated decisions individuals make. While Symbolic Interactionism also analyzes social interaction on a micro level with a focus on communication and shared symbols, Rational Choice Theory more directly centers on the costs and benefits affecting individual choices.