The correct option is A In
Here, 'in' is correct because it implies directly. Here, starvation stared him 'directly'.
'At' is incorrect because it is used to say where something/somebody is or where something happens.
'On' is incorrect because it implies in or into a position covering, touching or forming part of a surface.
'For' is incorrect because it implies used to show who is intended to have or use something or where something is intended to be put.