An company operates a piecework system of remuneration, also guarantees its employees 80% of a time-based rate of pay which is based on $20 per hour for an 8 hour working day. Three minutes is the standard time allowed per unit of output.

Piecework is paid at the rate of $18 per standard hour, If an employee produces 200 units in 8 hours on a particular day, what is the employee's gross pay for that day?

A $128

B $144

C $160

D $180