1. illustrates
2. shows
3. explains

It’s better not to use ‘shows’ as then you are copying from the question. Graphs are not an explanation, so it is not ‘explains’. So ‘illustrates’ is best.

1. increased steadily
2. fluctuated
3. fell steeply

Looking at all the expenditure items, the changes are quite erratic over the whole time frame, so ‘fluctuation’ is the best description.

1. the most
2. the least
3. the highest

More was spent on food than clothing and gas, so ‘the most’ is correct. We can’t say ‘high money’.

1. a very similar trend to
2. the same trend as
3. an opposite trend to

They followed an opposite pattern, as food rose then fell.

1. dramatic fluctuation
2. fluctuated dramatically
3. fluctuating dramatically

The first and last options have no main verb, so it has to be the second choice ('Clothing expenses' is the subject for this verb).

1. was markedly dropping
2. drop markedly
3. dropped markedly

It is past simple for completed actions/events in the past, not past continuous (choice 1) or present simple (choice 2).

1. however
2. whereas
3. in contrast

‘However’ would need to follow a full-stop, as would ‘in contrast’. ‘Whereas’ is the only one that fits.

1. to finish at
2. to finalise at
3. finished at

The prepositional phrase fits. ‘Finalise’ is the wrong word form. It can’t be a main verb (finished) as there is no subject.

1. was more than half
2. was more than triple
3. was more than double

Around $310 was spent on food, with around $640 spent on clothing. So ‘more than double’ fits here.

1. an increase
2. spending increased
3. increasing

The last two choices do not fit grammatically. It should be the noun form.