9-11 please!

Linux based questions!

Thank you!

9. Which of the following strings does not match the regular expression Aa*b*c *? c. abcddd d. The empty string e. All of these match 10.Which of the following best explains the regular expression [0-9].*? a. A string containing only digits b. A string containing exactly one digit c. A string containing at least one digit d. A string starting with one digit e. A string starting with one digit followed by any non-digit characters 11.A US social security number is a 3-digit number, a hyphen, a 2-digit number a hyphen and a 4-digit number. Define a regular expression to match a social security number