QUESTION 12 To determine whether a character entered is a letler of the alphabet, use this function O isdigit O alphaolk O isalpha O None of these QUESTION 13 To Lest whether a character is a numeric digit char acter, use this furnction. O noLAlpha O isnumeric O isdigit O None of these QUESTION 14 To Lest whether a character is a printable character, use this Function o isprin o isprintok o isoktoprin O None of these QUESTION 15 What is the output of the following siatemen O upper case z O lower case O a lower case z followed by an upper case Z O a compiler error O None of these QUESTION 16 Which statement converts the sring "10 to the integer value 10? O itoa(10) O None of these