Final answer:
Astronomy is the most relevant skill for studying time zones, as it involves understanding the Earth's rotation and its relation to the sun, which dictates the division of the Earth into time zones.
Step-by-step explanation:
The question, "Which skill would be the most useful in studying time zones?" can be answered by looking at the nature of time zones and their relation to various disciplines. The correct answer is d) Astronomy, which is a branch of science dealing with the study of celestial bodies, and helps us to understand the concept of time zones through the Earth's rotation in relation to the sun. While time zones could involve some mathematical calculations for precise timekeeping or converting between different time zones, the fundamental concept is rooted in the Earth's rotation and its relation with celestial bodies, which falls under the field of astronomy.
Astronomy is instrumental in the division and understanding of time zones as it is directly related to the position of the Earth in space and the observation of celestial events that dictate the measurement of time. The birth of astronomy also contributed to the understanding of how the Earth's rotation affects the concept of day and night, which is the basis for why time zones exist. Therefore, astronomy is the most useful skill in studying time zones.