Which of the following are subject pronouns in Spanish? Yo, nosotros, unos, unas

Yo, nosotros, él

Yo, los, las

los, las, unos, unas

The second one. Like normal English pronouns: he, she, it, we, etc. nosotros means we, yo means I, and él means he. Una or uno means “a” or “an” and those aren’t subject pronouns

Do you like the teacher? si, i like the teacher. no, i don't  like the teacher. yes, you like the teacher

Greeting is by kissing gently on the cheeks but never the lips