(d) a fungi, Rhizopus
Fungi like Rhizopus break down food material outside their body and then absorb it. This is saprotrophic nutrition.
The passage in section 5.2.2 explicitly states: "Some organisms break-down the food material outside the body and then absorb it. Examples are fungi like bread moulds, yeast and mushrooms." Rhizopus is a bread mould (fungus), so option (d) is correct. Cuscuta and Tapeworm are parasites; Rhizobium is a symbiotic bacterium — none of these digest food externally before absorbing it.