Answer :

DenisAdi
triangle: no parallel sides
square: 2 pairs of parallels (2 opposite sides are parallels)
trapezoid must have 1 pair of parallels
pentagon: if regular then no parallel, if not regular there can be 1 or 2 pairs of parallels
Jamieandej

Answer:

triangle: none

square: 2 parallels

trapezoid: 1 parallel

pentagon: none