Step 1: Understanding the Concept
Sertoli cells are the supporting cells in the seminiferous tubules.
Step 2: Check the statements
They are few and lie among the germ cells, and they are called nurse cells.
They give attachment to spermatids and nourish them.
They are somatic cells, with a single diploid nucleus, so they are not multinucleate and haploid.
Step 3: Conclusion
The statement about multinucleate and haploid is incorrect.
Final Answer:
Sertoli cells are diploid with one nucleus.
\[ \boxed{\text{(C) }\text{They are multinucleate and haploid.}} \]