$74.$ Bethany incurred $$20,000$ in research and experimental costs for developing a specialized product during July $2023.$ Bethany went through a lot of trouble and spent $$10,000$ in legal fees to receive a patent for the product in August $2025.$ Bethany expects the patent to have a remaining useful life of $10$ years.

a$.$ What amount of research and experimental expenses for $2023,2024,$ and $2025$ may Bethany deduct?

b$.$ How much patent amortization expense would Bethany deduct in $2025?$