The word "empirical" in Para. 3 most probably means" ______".

A．follow a direct line of ascent
B．also appeal greatly to adults
C．are not characterized by technological progress
D．reflect the pace of social progress

A．The craftsmanship in toy making has remained essentially unchanged.
B．Toys have remained basically the same all through the centuries.
C．The toy industry has witnessed great leaps in technology in recent years.
D．Toys are playing an increasingly important role in shaping a child's character.