Which one of the following is a saprophyte ?

Which one of the following is a saprophyte ?

Cuscuta
Rhizopus
Spirogyra
Grass
This question was previously asked in
UPSC CDS-2 – 2023
A saprophyte is an organism that obtains its nutrition from dead and decaying organic matter.
Rhizopus is a genus of fungi, commonly known as bread mould. Fungi are heterotrophic organisms, and many, including species of Rhizopus, are saprophytes, digesting dead organic material externally before absorbing the nutrients.
Cuscuta is a parasitic plant that derives nutrients from a living host plant. Spirogyra is a filamentous green alga and an autotroph (producer) capable of photosynthesis. Grass is a plant and also an autotroph.