Dehydration of the following alcohol can give three isomeric unsaturated compounds. The order of increasing yields (lowest first) is...

a) 1-butyne, 1-butene, 2-butene
b) 2-butene, 1-butene, 1-butyne
c) 1-butene, 2-butene, 1-butyne
d) 1-butyne, 2-butene, 1-butene