Complex sentence: The CS100 version of the CSeries is to compete with the Embraer E195-E2, while the CS300 is to compete with the Boeing 737 MAX 7, Airbus A319 NEO, and Irkut MC-21-200.
Split into simpler sentences: The CS100 version of the CSeries competes with the Embraer E195-E2. The CS300 version of the CSeries is to compete with the Boeing 737 MAX 7, Airbus A319 NEO, and Irkut MC-21-200.