Liz is selling hand made door signs on eBay. The signs are currently priced at $40/shirt. Liz is not happy with her current revenue stream and asks Brad for advice. Brad estimates that the demand Liz's signs is: Q = 1000 - 10P (P = 100 - 0.1Q). If Liz is looking to maximize revenue, what should Brad's recommendation be?

Group of answer choices

Keep prices at $40/shirt

Raise prices to $50/shirt

Lower price to $20/shirt

Lower price to $25/shirt

Raise prices to $80/shirt