Final answer:
The concept that most closely follows current geological thinking is uniformitarianism, the principle stating that Earth's surface has been shaped by slow-moving geological processes that operate consistently over time. Thus, the correct option is A.
Step-by-step explanation:
The current geological thinking most closely follows the concept of uniformitarianism. This idea, championed by notable geologists like Charles Hutton and later Charles Lyell, suggests that the geological processes we observe shaping the Earth's surface today have been working in much the same way in the past.
Lyell's treatise, Principles of Geology, popularized the view that these processes are slow and gradual, such as the weathering and erosion from wind and rain creating valleys and other landforms. Uniformitarianism also implies the Earth is significantly older than what was previously believed based on biblical chronology. This principle contrasts with catastrophism, suggested by Georges Cuvier, which proposed that Earth's geologic features are primarily the result of rapid, catastrophic events like floods or earthquakes.
Under the principle of uniformitarianism, phenomena such as continental drift, mountain building, and the creation of the Hawaiian island chain are understood as results of continuous processes over vast periods of time, as opposed to singular, catastrophic events.