In a fertilized ovule, n, 2n and 3n conditions occur respectively in:
a) Antipodal, zygote and endosperm
b) Zygote, nucellus and endosperm
c) Endosperm, nucellus and zygote
d) Antipodals, synergids and integuments

Options

A. Antipodal, zygote and endosperm
B. Zygote, nucellus and endosperm
C. Endosperm, nucellus and zygote
D. Antipodals, synergids and integuments

Explanation

To solve the question regarding the ploidy levels in a fertilized ovule, we need to understand the different components involved in the fertilization process and their respective ploidy levels.

### Step-by-Step Solution:

1. **Identify the components of a fertilized ovule:**
- A fertilized ovule consists of several structures, including the zygote, endosperm, and antipodal cells.

2. **Determine the ploidy of the zygote:**
- The zygote is formed when the male gamete (pollen) fertilizes the female gamete (egg cell). Since the egg cell is haploid (n) and the pollen is also haploid (n), their fusion results in a diploid zygote (2n).

3. **Determine the ploidy of the endosperm:**
- The endosperm is formed from the fusion of one male gamete with two polar nuclei in the embryo sac. This results in a triploid structure (3n) because it combines three sets of chromosomes (one from the pollen and two from the polar nuclei).

4. **Determine the ploidy of the antipodal cells:**
- Antipodal cells are located at the opposite end of the embryo sac and are derived from the megasporangium. They are haploid (n) as they develop from the megaspore.

5. **Summarize the ploidy levels:**
- Antipodal cells: n
- Zygote: 2n
- Endosperm: 3n

6. **Match the ploidy levels with the options given:**
- Option A: Antipodal (n), Zygote (2n), Endosperm (3n) - This matches our findings.
- Option B: Zygote (2n), Nucellus (2n), Endosperm (3n) - Incorrect, as the nucellus is diploid (2n) but is not part of the fertilized ovule's ploidy levels.
- Option C: Endosperm (3n), Nucellus (2n), Zygote (2n) - Incorrect, as it does not follow the order required.
- Option D: Antipodals (n), Synergids (n), Integuments (2n) - Incorrect, as it does not match the required order.

7. **Conclusion:**
- The correct answer is **Option A: Antipodal (n), Zygote (2n), Endosperm (3n)**.