The hypothesized bat in question, if it was really a wet-market outbreak, was imported from hundreds of miles away.
Those in favour of the lab leak hypothesis point out that the virus showed up on the scene with all the evolutionary capability to spread amongst humans i.e with batteries included.
With previous Sars viruses my understanding is that each zoonotic jump was traceable with examples of previous forms in prior animal hosts to corroborate the lineage.
What makes Covid-19 interesting is that these zoonotic jumps or the gain of functions can be accelerated in the lab with the purpose of preparing us ahead of time for a dangerous forms of Sars style viruses. It looks like covid-19 may be that type of strain, not man made, but given the lab conditions for it to gain the capability. It may have escaped.
It's worth exploring the lab leak hypothesis but I would say that it's not politically expedient for any of the scientists or parties involved. We will never really know the truth and that is something we need to grow comfortable with.
My understanding is that A) is very much possible because it has happened before (SARS), but we have no evidence yet (and might never acquire).
For B) however, from my limited understanding, there is no strong evidence. We only know about a fraction of existing coronaviruses out there and given we observe one, that has caused a pandemic, the (conditional!) probability that it is well adapted is extremely high (survivorship bias).
If you have a credible source that claims B) please share it.