Final answer:
A coarse-clast conglomerate with large rounded pebbles and cobbles would most likely be deposited in a mountain stream, which is a high-energy environment capable of transporting and depositing large sediments.
Step-by-step explanation:
The coarse-clast conglomerate with fairly large rounded pebbles and cobbles is indicative of a high-energy depositional environment where strong currents can transport and deposit larger clasts. Among the options provided, a mountain stream best matches this description. Fast-flowing rivers in mountainous areas have the energy necessary to carry large sediments, which are then deposited as the water velocity decreases, forming a conglomerate. Desert environments typically involve finer wind-blown particles. Glaciers are known to carry a wide range of sediment sizes from clay to boulders (“poorly sorted” sediments), but glaciers do not typically round the clasts as well as running water. Lakes generally have quieter waters leading to the deposition of finer, well-sorted sediments.