What pattern attribute expression would you use to enter a product code that consists of
three digits, separated by a hyphen, and then a single lowercase letter?
a. [a-z]{1}-[0-9]{3}
b. [0-9]{3}-[a-z]{1}
c. [A-Z]{3}-[0-9]{1}
d. [0-9]{1}-[a-z]{3}