Here's a problem to solve: Which method is the safest way to watch an eclipse of the Sun?

Among the 4 following options, which is the correct answer?

- A: Turn away after two or three minutes.
 
- B: Look at the Sun through a long telescope.
 
- C: Cast an image through a pinhole onto a screen.
 
- D: Blink often until your eyes get used to the light.
 