Write an html document that includes an anchor tag that calls a php document. also, write the called php script document, which returns a randomly chosen greeting from a list of five different greetings. the greetings must be stored as constant strings in the script. a random number between 0 and 4 can be computed with these lines: # set the seed for mtrand with the number of microseconds # since the last full second of the clock mt_srand((double)microtime() * 1); $number = mtrand(0, 4); # computes a random integer 0-4