The word Zenith refers to the time at which something is most powerful or successful, or the point in the sky or celestial sphere directly above an observer. Metaphorically, it signifies the peak, climax, or apex of something. Therefore, the most accurate synonym among the choices is Highest point (option B).
When something reaches its zenith, it is at its absolute peak or maximum. For example, a career might reach its “zenith” during a period of great achievement, or the sun reaches its “zenith” at midday. Option A, “Lowest point,” is an antonym, referring to the nadir or bottom. Option C, “Center,” refers to the middle, which is not necessarily the highest point. Option D, “Edge,” refers to a boundary, which is also unrelated to the concept of a peak. Understanding “zenith” allows for precise description of moments of ultimate success, power, or elevation, highlighting the culmination of a process or trajectory.