Which of the following functions do not return a timestamp?
1. time()
2. date()
3. strtotime()
4. localtime()
5. gmmktime()

<?php
    echo (checkdate(4,31,2010) ? 'Valid' : 'Invalid');
?>

A. TRUE B. FALSE C. Valid D. Invalid

A. Integer B. String C. Boolean D. Float

A. T B. N C. E D. I

A. Complete text representation of month B. Day of month, with leading zero C. Daylight saving time D. Day of month, without zeros