In a turbine engine axial-flow compressor, statements: (1) each consecutive pair rotor and stator blades constitutes a pressure stage. (2) The number of rows of stages is determined by the amount of air and total pressure rise required. Regarding the statements

• A. only No.1 is true
• B. only No.2 is true
• C. neither is true
• D. both No.1 and No.2 are true

Answer: (D)