Centurion Processing Finishes the First Unit in 120 Hours and Learns

Centurion Processing finishes the first unit in 120 hours and learns at a 70% rate. Their competitor, Ochenta Incorporated, completes their fist unit in 80 hours but learns at an 80% rate. If they match total output with each other how many units must each fierce rival make before Centurion's cumulative processing time is lower than Ochenta's?

A) 30 units
B) 33 units
C) 36 units
D) 39 units