Task: Question Answering
Input (English): Problem: the youngest of 4 children has siblings who are 3 , 5 , and 8 years older than she is . if the average ( arithmetic mean ) age of the 4 siblings is 21 , what is the age of the youngest sibling ? 
Options: a ) 17 , b ) 18 , c ) 19 , d ) 21 , e ) 22
Output (English): a