$P =$ constant, Volume increases and temperature also increases

$\Rightarrow \quad W =$ positive,$\Delta U =$ positive

$\Rightarrow \quad$ Heat is positive and supplied to gas

Process - $2$

$V =$ constant, Pressure decrease

$\Rightarrow$ Temperature decreases

$W =\int pdV =0$

$\Delta T$ is negative and $\Delta U =\frac{ f }{2} nR \Delta T$

$\Rightarrow \quad \Delta U$ in negative

$\Delta Q =\Delta U + W$

$\therefore \quad \Delta Q \rightarrow$ Heat is negative and rejected by gas

Process $3$

$P =$ constant, Volume decreases

$\Rightarrow$ Temperature also decreases

$W = P \Delta V =$ negative

$\Delta U =\frac{ f }{2} nR \Delta T =$ negative

$\Delta Q = W +\Delta U =$ negative

Heat is negative and rejected by gas.

Process $4$

$V =$ constant, Pressure increases

$W =\int pdV =0$

$PV = nRT \Rightarrow$ Temperature increase

$\Rightarrow \quad \Delta U =\frac{ f }{2} nR \Delta T$ is positive

$\Delta Q =\Delta U + W$

$=$ positive

Ans. $(C)$ step $1$ and step $4$