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It's possible that the earth's continents were once joined in a single giant landmass. The reason is that the earth's crust is divided into separate tectonic plates. If earthquakes occur, and they do, then the plates must be moving. If the crust is divided into separate plates and the plates are moving, then it's possible that the continents were once joined in a single giant landmass.

(use long truth table technique)

a.

This is an invalid argument

b.

The conclusion column shows no Fs

c.

The conclusion column shows all Ts

d.

The conclusion column shows some Fs

e.

This is a valid argument