Final answer:
A braided river is most likely to deposit a conglomerate due to its variable and energetic flow capable of transporting and depositing large, rounded clasts. Sand dunes, meandering rivers, and landslides generally do not have the flow characteristics necessary to deposit conglomerates.
Step-by-step explanation:
The environment most likely to deposit a conglomerate is a braided river. Conglomerates are coarse-grained sedimentary rocks that have a variety of rounded clasts. These clasts are typically greater than 2 millimeters in diameter, and they are held together by a matrix consisting of smaller particles and a mineral cement that binds the rock together. In a braided river environment, the water flow can be highly variable and energetic, which is capable of transporting and eventually depositing large, rounded clasts that form conglomerates. This contrasts with environments like sand dunes, meandering rivers, and landslides, which either have gentler flow regimes that cannot transport large clasts, or they deposit materials in a different manner.
When reviewing descriptions of environments, we can identify a braided river by the presence of mostly sand deposits with some sediment beds having a layer of gravel on the bottom and cross-bedding. This is indicative of the variable flow and sediment supply found in a braided river system. In contrast, a swamp or wetlands environment is usually characterized by fine sediment deposits with abundant organic material and very little gravel or cross-bedding.