Usually in a period of how many years does the Halley's Comet appear once?

Answer: Option 3

Explanation:

Halley's Comet or Comet Halley, officially designated 1P/Halley, is the best-known of the short-period comets and is visible from Earth every 75-76 years. Halley is the only short-period comet that is clearly visible to the naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. Other naked-eye comets may be brighter and more spectacular, but will appear only once in thousands of years. Halley last appeared in the inner Solar System in 1986 and will next appear in mid-2061. The comet is named after English astronomer Edmond Halley, who examined reports of a comet approaching Earth in 1531, 1607 and 1682. He concluded that these three comets were actually the same comet returning over and over again, and predicted the comet would come again in 1758. Halley didn't live to see the comet's return, but his discovery led to the comet being named after him.