The sentence shows the work is completed without a doubt.
- 'sloppy' means 'in a careless and unsystematic manner'
- the word 'haphazard' is used when something is done in unorganised or in random order.
so, these words can't replace 'through', here.
the word 'pretty' doesn't fit in this sentence.
so, Option "B." Complete is the correct choice.