Consider the following statements:
Automatic signalling system results in
1. greater risk
2. higher efficiency
3. avoidance of block instruments
4. higher operating cost
Of these statements

A. Stop B. Proceed C. Proceed cautiously D. None of the above

A. 25 mm B. 40 mm C. 50 mm D. 10mm

A. 12 m and 12 m B. 12 m and 13 m C. 13 m and 12 m D. 13 m and 13 m

A. 2 B. 3 C. 4 D. none of the above