Which among these is /are correctly matched ?

Options

A. Position emission : n/p ratio increase
B. K - electron capture : n/p decrease
C. `beta` - decay : n/p ratio decreases
D. `alpha`- decay : n/p ratio increases

Explanation

To determine which processes correctly match the changes in the neutron-to-proton (n/p) ratio, let's analyze each decay process mentioned in the question:

1. **Positron Emission**:
- In positron emission, a proton is converted into a neutron, resulting in a decrease in the number of protons and an increase in the number of neutrons. Therefore, the n/p ratio **increases**.

2. **Electron Capture**:
- In electron capture, an electron is captured by a proton, which transforms the proton into a neutron. This results in a decrease in the number of protons and an increase in the number of neutrons. Thus, the n/p ratio **increases**.

3. **Beta Decay**:
- In beta decay, a neutron is converted into a proton, which increases the number of protons and decreases the number of neutrons. Consequently, the n/p ratio **decreases**.

4. **Alpha Decay**:
- In alpha decay, the nucleus loses two protons and two neutrons (an alpha particle). This results in a decrease in both protons and neutrons, but the ratio of neutrons to protons can vary depending on the original nucleus. Generally, the n/p ratio **decreases**.

Now, let's summarize the findings:

- **Positron Emission**: n/p ratio **increases** (correct)
- **Electron Capture**: n/p ratio **increases** (correct)
- **Beta Decay**: n/p ratio **decreases** (correct)
- **Alpha Decay**: n/p ratio **decreases** (not correctly matched)

Based on this analysis, the correctly matched processes are:
- Positron Emission
- Electron Capture
- Beta Decay

### Final Answer:
The processes that are correctly matched regarding the neutron-to-proton ratio are:
- Positron Emission (n/p ratio increases)
- Electron Capture (n/p ratio increases)
- Beta Decay (n/p ratio decreases)