91Ó°ÊÓ

Before evaluating the options, let's understand the different nuclear decay processes. In positron emission, a proton is transformed into a neutron, thereby decreasing the proton number which generally increases the neutron-to-proton (n/p) ratio. In K-electron capture, an inner electron is captured by the nucleus causing a proton to become a neutron, also increasing the n/p ratio by reducing the number of protons. In β-decay (beta-minus decay), a neutron is converted into a proton, thus increasing the proton number and decreasing the n/p ratio. In α-decay, an alpha particle (2 protons and 2 neutrons) is emitted. While both protons and neutrons decrease, they do not always change the n/p ratio significantly compared to positron emission or beta decay.

In positron emission, the proton count decreases while neutrons increase, which causes an increase in the n/p ratio. Therefore, option (a) is correctly matched.

For K-electron capture, a proton is converted to a neutron, thus increasing the number of neutrons and decreasing the number of protons, which results in an increased n/p ratio. Therefore, option (b) is incorrectly matched because it said n/p ratio decreases.

In β-decay, a neutron is converted into a proton, thus increasing the number of protons and decreasing the number of neutrons, leading to a decrease in the n/p ratio. Therefore, option (c) is correctly matched.

In α-decay, the removal of 2 protons and 2 neutrons should technically reduce both the neutron and proton numbers equivalently, often not increasing the n/p ratio significantly unless in specific isotopes. Therefore, option (d) is incorrectly matched if generalized.