I agree, some of the sentences are strange. If you check the possibilites one by one:
A) HOWEVERr = This actually kind of makes sense, as it is at least showing some contrast, but it's not the best choice.
B) BESIDES / C MOREOVER = both of these mean something like 'in addition to', which doesn't make sense because the sentence is making a contrast between using spoons or forks (which isn't happening) and whatever is happening.
D) INSTEAD this is the best aswer. The sentence is saying they don't use forks, then it says what they use in place of forks to do the same task. INSTEAD = in place of, so it's the best answer.