Answer:
Cambridge English Dictionary defines "espouse" as "to support an activity or opinion."
2. So, the correct meaning of the "espouse" from the given options is "Support."
Cambridge English Dictionary defines "doctrine" as "a principle or set of principles that are followed by a particular group or in a particular situation."
4. So, the correct meaning of the "doctrine" from the given options is "Principle."
Cambridge English Dictionary defines "precarious" as "in danger because not firmly fixed; likely to fall or suffer harm."
1. So, the correct meaning of the "precarious" from the given options is "Insecure."
Even though you didn't give us the fragment with the comma slice, it isn't really necessary here as we can answer just based on these 4 options here. All options apart from the second one are correct - only the second option doesn't fix the mistake of the comma splice, whereas the other options do but connecting the sentences properly.
The correct English term for words that have the same spelling and pronunciation but multiple( ie different) meanings is 'homonyms'.
EG. 'Duck'
A duck flew over.
The boy should duck before he hits his heat on the branch.
