Final answer:
A star with a mass less than 0.08 times the mass of the Sun is most likely to be considered a brown dwarf. Brown dwarfs are objects that cannot sustain hydrogen fusion, being in the mass range between about 1/100 to about 1/12 the mass of the Sun and can fuse deuterium.
Step-by-step explanation:
The star-like object that would most likely be considered a brown dwarf is a star with a mass less than 0.08 times the mass of the Sun. Brown dwarfs are defined as objects with masses between about 1/100 to about 1/12 the mass of the Sun, capable of deuterium fusion but not hot enough to sustain hydrogen fusion. A brown dwarf can be thought of as an intermediate object in size between a planet and a star, where the upper mass limit is too low for sustaining the nuclear reactions that define true stars.
Stars with masses greater than 0.08 times the mass of the Sun typically have enough mass to sustain nuclear fusion and are thus considered true stars, not brown dwarfs. In comparison, brown dwarfs have masses that range roughly from 13 to 80 times that of Jupiter, or approximately 0.0125 to 0.08 that of the Sun, fitting the criterion for option 1).