With certain exceptions, class e airspace extends upward from either 700 feet or 1,200 feet agl to, but does not include, a) 14,500 feet msl.* b) 18,000 feet msl. c) 10,000 feet msl.

B) 18,000 feet MSL

Explanation:

There are three-dimensional parts in the navigation airspace in the world. The class E airspace is mostly used in the regions with coastal areas that are relatively populated. If we consider certain forms of exceptions, the class E airspace can move in the upward direction to few feet (i.e. 1200 ft). However, this doesn't include 18,000 feet MSL.

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