During 2020, Starnes Corporation developed a patent. Starnes incurred the following costs related to the development of the patent: tests to perfect the use of the patent for production processes, $5,400; research costs in the research laboratory, $18,900; and depreciation on equipment (that has alternative future uses) used in developing the patent, $3,600. In addition, in late December 2020, the company incurred legal fees for the patent registration, $6,300. The expected life of the patent is 20 years. On September 30, 2021, Starnes Corporation defended its patent in court after incurring legal fees of $2,700. The total estimated life of the patent at that time was adjusted to 15 years remaining from September 30, 2021. Record journal entries for the following items. Required:
a. Patent development and registration costs incurred in 2020.
b. Legal fees paid in 2021.
c. Amortization expense in 2021.
d. Amortization expense in 2022c. Amortization expense in 2021.