Which of the following types of stars is most likely to end up as a supernova?

The graph A is the right answer.

Explanation:

A supernova happens when there is a change in the nucleus, or center, of a star. A change can occur in two different ways, with both resulting in a supernova.

As the star runs out of nuclear fuel, some of its mass flows into its nucleus. At that moment the wavelength emia by the star exceeds 700 nm / s. Eventually, the core is so heavy that it can not withstand its own gravitational pull. The nucleus collapses, resulting in the giant explosion of a supernova.

the only real purpose of sputnik 1 was to beat the us into space. we were getting close to launching a useful satellite, explorer 1 - which launched on january 31, 1958. the ussr had to beat that, so they launched sputnik 1 on october 4, 19

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.