Lets check each option one by one A. \\\\(9\\\\) divisor are \\\\(1\\\\) and \\\\(3\\\\). \\\\(1+3=4\
eq 9\\\\) so not a perfect number.B. \\\\(15\\\\) divisors are \\\\(1, 3,\\\\) and \\\\(5\\\\). \\\\(1+3+5=9\
eq 15\\\\) so not a perfect numberC. \\\\(21\\\\) divisors are 1, 3 and 7. \\\\(1+3+7 = 11\
eq 21\\\\), so not a perfect number.D. \\\\(6\\\\) divisors are \\\\(1,2\\\\) and \\\\(3\\\\). \\\\(1+2+3 =6\\\\) It is a perfect number So correct answer is option D