Which of the following best describes the term "beta" in a scientific or technical context?
a. A type of particle in nuclear physics that is emitted during radioactive decay, known as a beta particle.
b. A phase in the software development cycle where a program is released to a limited audience for testing before the final release.
c. A measure of the intensity of light emitted from a source in photometry.
d. A specific enzyme involved in the breakdown of carbohydrates in biochemical processes.