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

To find the correct match between List - I and List - II, let us analyze the phases of the cell cycle and their respective events:

1. S phase (Synthesis Phase):
During the S phase of the cell cycle, DNA replication takes place. The amount of DNA per cell doubles, though the chromosome number remains the same.
Therefore, (a) matches with (iv) DNA replication.

2. G₂ phase (Gap 2 Phase):
During the G₂ phase, cell growth continues, and proteins required for mitosis (such as tubulin) are synthesized in preparation for cell division.
Therefore, (b) matches with (i) Proteins are synthesized.

3. Quiescent stage (G₀ phase):
Some cells do not divide further and exit the G₁ phase to enter an inactive state called the quiescent stage (G₀). In this stage, cells remain metabolically active but no longer proliferate unless called on to do so depending on the requirement of the organism.
Therefore, (c) matches with (ii) Inactive phase.

4. G₁ phase (Gap 1 Phase):
Note: In List-I, row (d) is written as "G2 phase" due to a typographical error in the database, but based on the matches, it represents the G₁ phase.
The G₁ phase corresponds to the interval between mitosis and the initiation of DNA replication. During this phase, the cell is metabolically active and continuously grows but does not replicate its DNA.
Therefore, (d) matches with (iii) Interval between mitosis and initiation of DNA replication.

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