Task: Question Answering
Input (English): Problem: there are 4 runners on a track team who run an average of 4.5 seconds per 40 yards . if another runner joins their team who runs 4.3 seconds per 40 yards , what will the new average 40 yard time be ? 
Options: a ) 4.46 , b ) 4.39 , c ) 4.42 , d ) 4.49 , e ) 4.33
Output (English): a