B (the first one in the array is arry[0] and the last one is 9. Excluding cd, the choice of ab is simple.

three-dimensional

There is no correct answer, it should correspond to the character 9, and the number after/should be octal or hexadecimal. Obviously, the assignment method is incorrect, and the computer reads the following character 9 when inputting.

Five b belongs to the error of no hierarchy. Cd is allowed, but it can only be empty.

Six aces

Seven d's

Eight a

In fact, I don't quite understand your question, whether the comparison of strings and the use of strcmp function are the same; Why is there something equal to zero? D is the same as both, and A is a logical operation between two characters or values.

Note that there should be quotation marks in putchar(c)

The output result is c* hehe.

In fact, many of the above problems can be run directly in VC++ ...