Which of the Following Conditions Tend to Cause Laminar Flow

Which of the following conditions tend to cause laminar flow to become turbulent (producing a high Reynold's number) ?
1) High linear gas velocity
2) High gas density
3) Low gas viscosity
4) Smaller tube diameter

A) 2, 3, and 4 only
B) 2 and 3 only
C) 1, 2, and 3 only
D) 1 and 4 only