Answer:
A) Contigo; conmigo.
Step-by-step explanation:
-A Lidia le gustaría salir contigo.
-¿Por qué?
-Le gustas tú.
-Tú eres mi novia. Tú estás conmigo. No quiero salir con Lidia.
English:
-Lidia would like to go out with u.
-Why?
-She likes u.
-You're my gi rlfriend. U are with me. I don't want to go out with Lidia.