Answer:
1. B
2. D
3. A
Step-by-step explanation:
If I understood correctly, the task here is to find the meaning of the given phrases.
"Help yourself" is a phrase that means "feel free to eat/drink/try". It is usually said in big lunches or dinner, for holidays, or whenever there are guests present.
"Make yourself at home" is a phrase spoken to a guest. It literally means "feel free and comfortable as if you were at your own home".
"Be my guest" is a phrase used to give permission or approval to a previously posed question. It literally means "yes, of course, go ahead".