let the numbers be ->
x1,x2,x3,x4,x5...the mean given is 12..so
(x1+x2+x3+x4+x5)/5=12..
x1+x2+x3+x4+x5=60 ...
Option D can't be the answer cause the question says"Different" Natural numbers..for 60 ..4 numbers should be 0 and that here is not true..
Option C seems to be the correct one as -> 50+x2+x3+x4+x5=60...x2,x3,x4,x5 can be 1,2,3,4 also..