Here are the rules by which we must abide:
There's no great way to draw Relative Ordering trees in this typing environment, but essentially we know that
G, K - (HF)
and
K - J
Q4 is a "Fully determined" question, meaning that the correct answer will lock in a complete scenario, while the four incorrect answers will leave some indeterminacy.
Before you dive in to the answers, it's good to try to get a good intuitive guess for what indeterminate parts need to be nailed down.
1. We need to nail down the order of the (HF) chunk.
2. We need to nail down the order of G vs. K
3. We need to know whether J comes before the (HF) chunk or after it.
(A) FH
That only gives us 1. Still no clue about 2 or 3
(B) GF
That gives us 1, GFH.
That gives us 2, because K must come before GFH.
But, we still don't know whether J comes before GFH or after it.
KJGFH or KGFHJ?
(C) HJ
That gives us 1, FHJ
That gives us 3, because J comes after the chunk.
But we still don't know 2. Who's first? G or K?
GKFHJ or KGFHJ?
(D) JH
That gives us 1, JHF
That gives us 3, because J comes before the chunk.
But we still don't know 2. Who's first? G or K?
GKJHF or KGJHF?
(E) KF
That gives us 1, KFH
That gives us 3, because J comes after the chunk.
That gives us 2, because G must be first.
GKFHJ
(By the way, this may be my own paranoia, but it seems like questions like these in which you HAVE to test the answer choices, it sometimes pays to start from the bottom and work your way up ... LSAT might be hiding the correct answer towards the bottom so that we have to spend more time to get to it)
Hope this helps.