Read the following topic sentence from an expository essay:
Knowing what to bring along is one way to make air travel more
convenient.
Which supporting detail would best develop this topic?
A. Air travel generally costs more than traveling by train.
B. Passengers must provide identification and a ticket before
boarding
C. Sturdy shoes are a must for most trips, especially those that
involve walking.
D. The Universal Airlines website says, "Passengers must remain
seated during takeoff and landing."