The process in which a diploid egg cell is formed which later develops into an embryo without fertilisation is called:

Options

A. Parthenogenesis
B. Parthenocarpy
C. Polyembryony
D. Agamospermy

Explanation

To solve the question, we need to identify the correct term for the process in which a diploid egg cell develops into an embryo without fertilization. Let's break down the options provided:

1. **Parthenogenesis**: This is a form of asexual reproduction where an egg develops into an organism without fertilization, but it typically refers to the development of an entire organism rather than just an embryo.

2. **Parthenocarpy**: This refers to the development of fruit without fertilization, which is not relevant to the formation of an embryo from a diploid egg cell.

3. **Polyembryony**: This is a phenomenon where multiple embryos develop from a single fertilized egg, which again does not fit the description of the question.

4. **Agamospermy**: This is the process where seeds are produced without fertilization, and it involves the development of an embryo directly from the diploid egg cell.

Given these definitions, the correct answer is **Agamospermy**. This process allows the formation of embryos from diploid egg cells without the need for fertilization, which aligns perfectly with the question's requirements.

### Step-by-Step Solution:
1. **Identify the Process**: Understand that the question is asking for a process where a diploid egg cell forms an embryo without fertilization.

2. **Evaluate the Options**: Analyze each option provided:
- Parthenogenesis: Involves the development of an organism, not just an embryo.
- Parthenocarpy: Involves fruit development, not embryo formation.
- Polyembryony: Involves multiple embryos from a fertilized egg.
- Agamospermy: Involves embryo development from a diploid egg without fertilization.

3. **Select the Correct Answer**: Based on the analysis, choose **Agamospermy** as it directly relates to the formation of an embryo from a diploid egg cell without fertilization.