Answer:
C. Places both beakers in a freezer at a temperature of l°C
sentences 10 and 11
Step-by-step explanation:
It's not A because they're comparing fresh water and salt water.
It's not B because they're trying to also find out their freezing rate comparative.
It's not D because they're trying to compare the freezing rates and they need them at the same temperature. Also said in sentence eight that they do that anyways.
It's easy to see that sentences 10 and 11 contains the conclusion if you just read the two.