Each chapter of the book ends with a Certification Practice question that's comparable to what you could expect to be asked on a Java certification test. Here's the answer for chapter 19:
Answer (c) is correct. Because the nameCount variable is not incremented anywhere else in the class, it must be incremented in this statement. Using ++ as a postfix operator after the variable name causes nameCount to be incremented by one after it is used as an index to the names array.
Answer (d) is incorrect. The nameCount variable is incremented in this statement, as it should be. However, ++ is used as a prefix operator before the variable name, which causes nameCount to be incremented by one before it is used as an index to the names array. For this reason, the names array only can store 19 elements, because it never assigns a name to names[0].
Answer (a) is incorrect. The nameCount variable never changes from its initial value of 0, so the names array only can store 1 name instead of 20.
Answer (c) is incorrect. The == operator is used to compare two sides of an expression for equality. If you tried to compile the program, it would fail with the error message "not a statement" associated with this line. 
