For Which of the Following Purposes Might a Venturi Tube

Multiple Choice

For which of the following purposes might a Venturi tube be used?
1) To restore fluid pressure distal to a restricted orifice
2) To help keep entrainment ratios constant with varying flows
3) To make possible entrainment of large volumes of gas

A) 1, 2, and 3
B) 2 and 3 only
C) 1 and 2 only
D) 1 and 3 only