Luminosity is a measure of the amount of light a star directly emits.
Answer : Option A
Step-by-step explanation:
Light intensity is similar to brightness of the light where it is a measure of amount of light focused with respect to area and its unit is called as lux represented by lx.
Different light has different wavelengths according to the electromagnetic spectrum. Luminosity is the best option from the given ones as is a measure of amount of light emitted from an object which is here referred to a star.