Which one of the following precedes re-formation of the nuclear envelope during M phase of the cell cycle.

Options

A. Transcription from chromosomes and reassembly of the nuclear lamina
B. Formation of the contractile ring and formation of the phragmoplast
C. Formation of the contractile ring and transcription from chromosome
D. Decondensation from chromosomes and reassembly of the nuclear lamina

Answer

To determine which process precedes the reformation of the nuclear envelope during the M phase of the cell cycle, we need to analyze the events that occur during this phase, particularly focusing on the anaphase and telophase stages.

### Step-by-Step Solution:

1. **Understanding M Phase**: The M phase (mitotic phase) includes both mitosis and cytokinesis. Mitosis is divided into several stages: prophase, metaphase, anaphase, and telophase.

2. **Anaphase Events**: During anaphase, the sister chromatids are pulled apart toward opposite poles of the cell. This is a crucial step where the genetic material is segregated.

3. **Transition to Telophase**: After anaphase, the cell enters telophase. This is where the separated chromatids (now individual chromosomes) begin to decondense, and the nuclear envelope starts to reform around each set of chromosomes.

4. **Decondensation of Chromosomes**: Before the nuclear envelope can reform, the chromosomes must decondense. This means that the tightly packed chromatin unwinds to allow for the formation of the nuclear envelope.

5. **Reassembly of Nuclear Lamina**: The nuclear lamina, a network of protein filaments inside the nuclear envelope, begins to reassemble as the chromosomes decondense. This is essential for the reformation of the nuclear envelope.

6. **Reformation of Nuclear Envelope**: Finally, once the chromosomes have decondensed and the nuclear lamina has reassembled, the nuclear envelope can reform, enclosing the chromatin and separating it from the cytoplasm.

### Conclusion:
The correct answer to the question is that the **decondensation of chromosomes and reassembly of the nuclear lamina** precedes the reformation of the nuclear envelope during the M phase of the cell cycle.