The internal mechanism of a mechanical Swiss watch is a marvel of engineering, forming an _______ system of gears and springs: the mainspring provides power, the balance wheel regulates time, and the escapement controls the release of energy, all working together in complex harmony.
Which choice completes the text with the most logical and precise word or phrase?
indecipherable
ornamental
obscure
intricate
Correct Answer: D
Choice D is the best answer. The text details how the many parts of the watch (gears, springs, wheels) work together in "complex harmony." This system is best described as "intricate" (very complicated or detailed).
Choice A is incorrect because "indecipherable" means impossible to understand, but the text clearly explains the mechanism. Choice B is incorrect because "ornamental" means decorative. Choice C is incorrect because "obscure" means not discovered or known about.