What regular expression would you use if you wanted to match either a six-digit or a three-digit hexadecimal color value? What is a verbal description of the kind of string that matches each of the...

What regular expression would you use if you wanted to match either a six-digit or a three-digit hexadecimal color value? What is a verbal description of the kind of string that matches each of the following regular expressions? a) ^[A-Z]\w{1,9}$ b) ^[21]9\d{2}$ c) ^[^aeiouAEIOU]$.