Which out of the following cannot produce two coherent sources?

The correct option is D Prism.

Lloyd's mirror is used to produce two coherent sources out of phase with each other, from a single source and its reflection from a mirror.

Fresnel biprism refracts light from a single source to create two virtual in-phase coherent sources.

Young's double slit produces two coherent sources by diffraction from two slits, the phase depending upon the position of the source with respect to the slits.

However, a single prism cannot produce two coherent sources.