Detailed Instructions: In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: 7 , 26 , 63 , 124 , ( . . . . ) 
Options: a ) 342 , b ) 125 , c ) 289 , d ) 564 , e ) 36
A:
a