Larry mows lawns for $50 an hour. Last week, he gave all his customers a 20% discount off his hourly rate. Mrs. Grinnell hired Larry last week to mow her lawn, and Larry applied a 10% new customer discount to his already discounted rate. If Larry worked on Mrs. Grinnell's lawn for 3 hours, how much does Mrs. Grinnell owe Larry? A
$60

B
$102

C
$105

D
$108