Two Electricians telling me two different things

I have a question I was hoping to get answered before I chose one of these two electricians to upgrade my service.

From the weatherhead to the meter and panel I have a 1-1/4 EMT with the three 4AWG wires feeding my vintage 50 amp service.

One electrician says he would need to replace the EMT to upgrade the service.

The other says three 2AWG wires are fine in 1-1/4 EMT.

I would prefer not opening up the wall and using the conduit that is already there, it is also part of his quote to replace it and I don't want to pay for something I don't need.

I guess, I am asking is

A: According to code, what is the largest 3 wires I can run through the 1-1/4

B: With that size wire, how many amp is the max that my service can be.

I really appreciate any advice or links to code references.

Thank you for your time

Also, I am in San Francisco California