The research and development expense of S Co. includes which of the following items: 1) Costs of advertising a newly invented product. 2) Billings received by S Co from Black Hole Sun Co. for research activities performed by Black Hole Sun Co. for S Co. 3) The depreciation on a building used in various R&D projects 4) Billings sent by S Co to Ugly Kid Joe Co. for research activities performed by S Co for Ugly Kid Joe Co. 5) Costs of materials, labor and overhead incurred in generating a patent. The patent was granted to S Co during the period. 6) Overhead costs properly allocated to the research and development activities performed by S Co during the period. P a g e | 15 7) Training costs of S Co employees who are directly involved in R&D projects. 8) The amortization of patents used in S Co research activities. a. 2, 3 & 6 b. 2, 3 & 8 c. 2, 3, 6 & 8 d. 2, 3, 5, 6 & 8 Provide with explanation