Given the task definition and input, reply with output. 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'.

Problem: how many 7 - digits number are palindromic numbers ? a palindromic number reads the same forward and backward , example 1234321 .
Options: a ) 100 , b ) 610 , c ) 729 , d ) 9000 , e ) 1000
d