Write the statement below as a bicondtional.
"when the sum of the digits of an integer is divisible by 9, the integer is divisible by 9."
if an integer is divisible by 9, then the sum of the digits of the integer is divisible by 9
the sum of the digits of an integer is divisible by 9 if and only if the integer is prime
the sum of the digits of an integer is divisible by 9 if and only if the integer is divisible by 9
if the sum of the digits of an integer is divisible by 9, then the integer is divisible by 9