PSU for EG912U, direct from battery or from buck boost?

Technical Subjects Hardware Baseband
1

Hi, I don’t understand what is the best solution for supply this module.
A B or C? I think the A is the most expensive, B middle and C less expensive.
Many Thanks.

image
image1204×834 118 KB

2

Please confirm if the battery used is a 4.2V lithium battery? If so, I think the C is the best option