Answer:
c. Ralph's classmate observing Daphnia in water at 30oC, 32oC and 34oC
Step-by-step explanation:
When we talk about replication, we actually mean, repetition of a scientific procedure carried out by another scientist and obtaining the same results as he/she previously did.
Replication is carried out under identical conditions as the first scientist did. If Ralph's classmate wants to replicate Ralph's work, then identical temperature conditions of 30oC, 32oC and 34oC must be used, hence the answer above.