I need solution to this SQL question: What SELECT statement would you use in a longer query to calculate the amount of money earned by each instructor based on the length of time for the class and $$20$ per hour? Display the instructor$$s last name and the amount earned.

a$.$ SELECT InstructorLastName, LengthofTime$*20$ AS Amount Earned

b$.$ SELECT InstructorLastName, LengthofTime$/60*20$ AS Earnings OF Instructor

c$.$ SELECT InstructorLastName, LengthofTime$/60*20$ AS AmountEarned

d$.$ SELECT InstructorLastName, JOIN LengthofTime$/60*20$ AS Amount Earned