The current stock price is $100. The yield curve is flat, and the interest rate is 5% per year, compounded annually. Consider options with a maturity of 2 years, and a strike price $90. You observe the following market prices for the call and the put options priced at C=$20 and P=$3. Assume that trading in option markets entails a cost of $x per transaction, i.e., each time an option is bought/sold, a cost x is incurred. Similarly, trading stocks incurs a cost of $y per share, i.e., each time a share of stock is bought/sold, a cost y is incurred. Saving or borrowing at the interest rate is not subject to transaction costs.

Question: What condition should x and y satisfy to guarantee the absence of arbitrage?