Excom sells radios and each unit carries a $2-$year replacement warranty. The cost of repair defects under the warranty is estimated at $5\%$ of the sales price. During September, Excom sells $100$ radios for $$50$ each. One radio is actually replaced during September. For what amount in September would Excom debit Product Warranty Expense?

a$.$ $$120$

b$.$ $$50$

c$.$ $$30$

d$.$ $$250$