ANS:C - rotary

For very low pressure and high discharge rate, the compressor used is an axial compressor. Here's why:

• Axial Compressors: These compressors are designed to handle large volumes of air at low pressure ratios, making them ideal for applications requiring high discharge rates at low pressures. They are commonly used in jet engines and large industrial processes where significant volumes of air need to be moved efficiently.
• Reciprocating Compressors: These are typically used for high-pressure applications and lower discharge rates. They use pistons to compress the air and are not as efficient for large volumes at low pressures.
• Rotary Compressors: These can handle a range of pressures and discharge rates, but for very high discharge rates at low pressures, axial compressors are generally more suitable.