Task: Question Answering
Input (English): Problem: a survey was taken among 100 brainiacs . of those surveyed , twice as many brainiacs likerebus teasers as math teasers . if 18 brainiacs like both rebus teasers and math teasers and 4 like neither kind of teaser , how many brainiacs like math teasers but not rebus teasers ? 
Options: a ) 17 , b ) 18 , c ) 19 , d ) 20 , e ) 21
Output (English): d