Consider the following statements relating to a closed gas turbine cycle.
1. The cycle can employ mono- atomic gas like helium instead of air to increases the cycle efficiency if other conditions are the same
2. The efficiency of heat exchanger increases with the use of helium
3. The turbine blades suffer higher corrosion damages.
4. Higher output can be obtained for the same size.
Which of these statements are correct?
a) 1,2 and 3 b) 1,2 and 4
c) 2,3 and 4 d) 1,3 and 4