A hint for multiple choice question Give me a hint to solve this question,

what should my first step ? 

should convert the grams into moles ?

aluminum= (54g/150g)= 36% ( percent composition of aluminum)
sulphur= 64%

0.36x=20 (36 percentage of what is 20)

x=20/0.36
x=55.5 grams

is there a more easy way ? to do in mind
You might consider writing a correctly balanced equation, and then convert grams to moles.