Describe a universal set U that includes all elements in the given sets of riversrivers. Upper AA equals= {Danube comma GangesDanube, Ganges} Upper BB equals= {Mekong comma Rio GrandeMekong, Rio Grande} Question content area bottom Part 1 Choose the correct universal set below. A. the set of all natural numbers B. the set of the elements DanubeDanube, Mekong comma and Rio GrandeMekong, and Rio Grande C. the set of all lakeslakes D. the set of all riversrivers