Excerpt from Batter Up: The Baseball Bat
Kathy Hufford

The first “official” baseball game was played in the early 1800s, more than 160 years ago. The equipment was simple: bat, ball, dirt playing field, and four wooden bases. No gloves.

In the early years, the players made their bats, all from wood. Eventually, batmakers found that the best style of the bat was long and slender, tapered, with a carved knob at the end of the bat for better control.

Although the first metal bat was patented in 1924, players did not start using metal bats until the first aluminum bats were developed in the 1970s. Bats made of aluminum became an instant success. They were light, durable, and easy to use, and players could hit the ball much farther than with a wooden bat. Unlike the wooden bat, a metal bat temporarily flexes when hit with the ball, and springs back, transferring more energy to the ball than a rigid wooden bat. This so-called “trampoline effect” is the secret of the metal bat’s superior performance over a wooden bat.

The design of bats continues to evolve as manufacturers search for ways to magnify the trampoline effect and increase the size of the bat’s “sweet spot” (the optimal place on the bat for hitting the ball). One design introduced in the late 1990s is a double-walled bat; this design comprises an outer wall of aluminum, an inner wall of a composite material (often graphite), and a “filling” of rubber or a thick fluid between the two walls.
If you were collecting information on how aluminum bats came to be used in college and high school baseball, which would the most appropriate note to take for the third paragraph of the passage?

A) aluminum bats work better
B) aluminum bats invented in the 70s
C) wooden bats invented in the 1800s
D) wooden bats don't work as well