4. Alexander Graham Bell is best known for inventing the telephone in 1876. This made him wealthy, and he used his money to invent many more things. Bell invented a type of metal detector, called an electric probe. Doctors used the probe to find metal pieces, such as bullets, in the human body, and it saved many lives. Bell also invented a vacuum jacket that forced air in and out of the lungs, helping people who had trouble breathing on their own. Bell experimented with flying machines and also built a boat called the hydrofoil. It was the fastest boat in the world for ten years.
The paragraph tells mainly
(A) why Bell used his money to invent things. (B) about Bell’s lesser known inventions.
(C) how Bell only invented things that saved people’s lives.
(D) which of Bell’s inventions was the best