Task: Question Answering
Input (English): Problem: in gabriel ' s sheep herd , every sheep has either fleas or lice or both . half of the sheep have lice , and 84 sheep have both pests . if 94 sheep have lice , how many sheep have only fleas ? 
Options: a ) 10 , b ) 20 , c ) 84 , d ) 94 , e ) 178
Output (English): a