According to my country's Patent Law, the term of an invention patent is ( ) years, calculated from the date of application.

Answer: B

This question tests the protection period of invention patents. Patent rights refer to the exclusive rights granted to applicants by the national patent office in accordance with the Patent Law within the statutory period for their inventions and creations. my country's "Patent Law" stipulates that the term of invention patents is 20 years, and the term of utility model and design patents is 10 years, both calculated from the date of application.