Help with SAT practice test question

what is the difference between “at which” “From which” “so that” and “whereby” ???

He placed the ball on the lamp, at which time he ate a banana.

He drove to Las Vegas, from which place he hooked up with some strippers.

She got in a car, so that she may eat some yogurt.

He got in the car, whereby he may press the gas pedal.

“at which” is a static location or time
_________ happens at that time or place.
EX. The library at which I most often study has plenty of private study rooms. (I study AT the library)

“From which” has an active indication
something is moving from something else
EX. The school from which I came has an excellent reputation. (I came FROM the school)

“So that” is to give a reason or ability to do something
EX. I read the book so that I could use it in my essay.

“Whereby” is almost equivalent to “how”, “by means which” or “through”
It is used to refer to a system, plan, or process with a specific result
EX. Reading widely is the best system whereby to acquire a large vocabulary.

It’s a way to avoid ending clauses with prepositions to fulfill a widely believed non-rule.

The bench on which I sit = the bench I sit on
The park at which I met you = the park I met you at
The country from which I came = the country I came from
(you see how the preposition is determined by the verb? Collocation ftw)

@academiccoach 's explanations of “so that” and “whereby” are good.

@studygirl89