Shiny Gem Diamond Cutters Supply House incurred $300,000 in factory overhead cost, of which $50,000 was identified as the cost of sanders for polishing tool bits. It also incurred rent of $75,000 for the building in which the tool bits and other products were manufactured. It paid $100,000 in sales commission for tool bits. Under activity-based costing, Shiny Gem will identify ________ as product cost for tool bits.

A : $250,000 B : $175,000 C : $150,000 D : $50,000