human
Question: Steel cans are separated from aluminum cans in a recycling center. Which of the following is the best way the recycling center can separate the steel cans from the aluminum cans?

Choices:
A) sort the cans by size
B) put the cans in water
C) cool the cans to a low temperature
D) put the cans under an electromagnet
gpt
The correct answer is 3: put the cans under an electromagnet.