Answer:
C. 84
Step-by-step explanation:
First, we will calculate the percentage of left-handed students in the group of 60 that the teacher asked.
So, the percentage is equal to:
Therefore, 30% of the randomly selected students are left-handed.
Now, we can use this percentage to estimate the number of left-handed students in the group of 280.
Then, 30% of 280 is equal to:
So, the answer is C. 84.