Question

in this sentence from the selection, the word “conventional” is used to mean
a ordinary
b public
c obedient
d artistic
the fans use half the number of blades, move 25 percent more air and use 25 percent less power than fans with conventional blades turning at the same speed.

Explanation:

The word "conventional" often means ordinary or typical in common - language usage. In the context of the fans, it is contrasting the new - type fans with the ordinary ones.

Answer:

A. ordinary