Concept: The question tests on the ability to solve a Word Problem
Solution:
1990-Bicycles produced= 0.42x
1993-Bicycles produced=0.33x
Bicycles were sold in 1990 and 1993 = x
=>The decrease in bicycles produced and sold in Western Europe from 1990 to 1993 was:
0.42(x) - 0.33(x)
= 0.09x
= 9 % of x
(option d)