The correct answer is: was invented.
The electric light bulb was invented by Thomas Edison in 1879. The word “invented” is the past tense of the verb “invent”, which means to create something new. In this case, Edison created the electric light bulb, which is a device that produces light by passing an electric current through a thin wire.
The other options are incorrect because they do not accurately describe the relationship between Edison and the electric light bulb. The word “invents” is in the present tense, which would imply that Edison is still inventing the electric light bulb. However, he invented it in 1879. The word “is invented” is also in the present tense, but it would imply that the electric light bulb is a new invention. However, it was invented over 140 years ago. The word “was invented” is in the past tense, which accurately reflects the fact that Edison invented the electric light bulb in 1879.