使用Objective-C语言输出“This is a Objective-Cprogram.”正确的是（）

A、NSLog(@"%s",This isa Objective-C program.);
B、NSLog(@"%@",This isa Objective-C program.);
C、NSLog(@"This is aObjective-C program.",%@);
D、NSLog(@"This is a Objective-Cprogram.");