Consider a cycle followed by an engine (figure). 

1 to 2 is isothermal,

2 to 3 is adiabatic,

3 to 1 is adiabatic.

Such a process does not exist, because:

Choose the correct alternatives:
1. (a, b)
2. (a, c)
3. (b, c)
4. (c, d)

A sink, that is, the system where heat is rejected, is essential for the conversion of heat into work. From which law does the above inference follow?
1. Zeroth
2. First
3. Second
4. Third