Which of the following statements about microeconomics and macroeconomics is not true ?

Which of the following statements about microeconomics and macroeconomics is not true ?

A. The study of very large industries is a topic within macroeconomics
B. Macroeconomics is concerned with economy-wide phenomena
C. Microeconomics is a building block for macroeconomics
D. Microeconomics and macroeconomics cannot be entirely separated