Point here to be noted is that when I write if (a >b) now after this I haven't written any braces so anything written within it would be considered as a single statement hence it is equivalent to if(a>b){ if (b < c) {s1 ;} else {s2 ;}
therefore clearly if s2 has to execute then we must have the condition a>b to be true simultaneously with b<=c , so option D is correct .