Explain one day's P/L, Greek by Greek

You are short a put. Interest rates rise one point. Which way does rho push your position, all else equal?

• Slightly in your favour, because short puts have positive rho
• Slightly against you, because all short options have negative rho
• Not at all, because rho only applies to calls

The Greeks on a screen come from a pricing model. Which of its inputs is solved backwards from the option's price?

• The strike
• Volatility
• Time to expiration