Were it not for the fusion-powered heat and radiation that rush from its core, instead its own weight would cause a star to collapse.

A. instead its own weight would cause a star to collapse
B. instead a star would have collapsed under its own weight
C. a star would have to be collapsing under its own weight
D. a star would collapse under its own weight
E. its own weight would have caused a star's collapse

OA: D

Is instead wrong here?
and i would like to know what's wrong with other options~
thank u so much!