Match List - I with List - II and choose the correct answer.

List - I	List - II
(a) S phase	(i) Proteins are synthesized
(b) G2 phase	(ii) Inactive phase
(c) Quiescent stage	(iii) Interval between mitosis and initiation of DNA replication
(d) G2 phase	(iv)  DNA replication

The correct option is a - (iv) b - (i) c - (ii) d - (iii).

Let us analyze the different phases of the cell cycle listed in List - I and match them with the correct processes in List - II:

(a) S phase (Synthesis Phase):
During the S phase, DNA replication occurs, leading to a doubling of the DNA content per cell without any increase in the chromosome number.
Hence, (a) matches with (iv) DNA replication.

(b) G₂ phase (Gap 2 Phase):
In the G₂ phase, the cell continues to grow and synthesizes proteins (such as tubulin) in preparation for mitosis.
Hence, (b) matches with (i) Proteins are synthesized.

(c) Quiescent stage (G₀ phase):
In this stage, cells exit the active cell cycle and enter an inactive state. The cells remain metabolically active but do not divide unless stimulated by appropriate environmental signals.
Hence, (c) matches with (ii) Inactive phase.

(d) G₁ phase (mislabeled as G₂ phase in List - I):
This phase represents the interval between the completion of mitosis and the initiation of DNA replication, during which the cell grows and is metabolically active.
Hence, (d) matches with (iii) Interval between mitosis and initiation of DNA replication.

Putting all the matches together, we get:
a - (iv), b - (i), c - (ii), d - (iii)