When a tetraploid individual is crossed with a diploid individual it producess triploid embryo, 5n endosperm and 4n fruit. In this cross the male individual is:

Options

A. Diploid
B. Tetraploid
C. 2n or 4n
D. None of these

Answer

To solve the question, let's break down the information given and analyze the genetic contributions from both the tetraploid and diploid individuals.

### Step 1: Understand the Cross
We have two individuals:
- A **tetraploid individual** (4n)
- A **diploid individual** (2n)

When these two are crossed, we need to determine the genetic contributions to the embryo, endosperm, and fruit.

### Step 2: Analyze the Embryo
The embryo produced is **triploid (3n)**. This means that the genetic contribution to the embryo comes from both parents.

- The diploid individual (2n) contributes **n** (haploid) via its pollen grain (after meiosis).
- The tetraploid individual (4n) contributes **2n** (diploid) from its egg cell (after meiosis).

Thus, the combination for the embryo is:
- From the diploid: **n**
- From the tetraploid: **2n**
- Total: **n + 2n = 3n** (triploid embryo)

### Step 3: Analyze the Endosperm
The endosperm produced is **pentaploid (5n)**. The endosperm is formed from the fusion of three nuclei:
- One from the egg (from the tetraploid, contributing 2n)
- Two from the polar nuclei (from the tetraploid, contributing 2n)

Thus, the total contribution to the endosperm is:
- From the diploid: **n**
- From the tetraploid: **2n + 2n = 4n** (from the two polar nuclei)
- Total: **n + 4n = 5n** (pentaploid endosperm)

### Step 4: Analyze the Fruit
The fruit produced is **tetraploid (4n)**. The fruit typically develops from the ovary of the flower, which contains the fertilized ovule.

The genetic contribution to the fruit is:
- From the diploid: **n**
- From the tetraploid: **2n**
- Total: **n + 2n = 3n** (but since the fruit is formed from the ovary, it retains the diploid contribution of the female, which is 2n, thus leading to the formation of a 4n fruit).

### Conclusion
From the analysis:
- The male individual must be the diploid (2n) because it contributes the haploid (n) for the triploid embryo and is consistent with the formation of the endosperm and fruit.

Thus, the answer to the question is:
**Option A: Diploid**