Low-temperature cascade system use refrigerants with ______ boiling temperature and high temperature cascade system use refrigerants with _________ boiling temperature.

Low-temperature cascade system use refrigerants with ______ boiling te

1.	Low-temperature cascade system use refrigerants with ______ boiling temperature and high temperature cascade system use refrigerants with _________ boiling temperature.
A.	low, high
B.	high, low
C.	low, low
D.	high, high
Answer» B. high, low