Alright, this is simple:
For reference material, you can use google, or a dictionary. Whichever you prefer. Though you should really know pretty much all of these words.
1. Utmost: Basically, this means "highest possible". For example: I have the utmost respect for you. I have the highest possible respect for you. A synonym for this would be extreme. An Antonym would be least, or limited.
Your answer for #1 is Least.
2. Upheaval. This basically means a sudden or violent change to a specified object.
Your answer here is G.
3. Commerce. This has a meaning that is generally associated with business, such as buying or selling, or trading. The answer that fits this best is:
Exchange
4. Fluent. This generally means "with ease", or "gracefully", and is generally associated with written or spoken language, as well as actions.
The answer that best fits this: i: Able to speak or write a language easily.
~Hope this helps!