First, we need to calculate the total number of pets by multiplying the number of students by the number of pets they have:
(3 students * 0 pets) + (4 students * 1 pet) + (2 students * 2 pets) + (6 students * 3 pets) + (2 students * 4 pets) + (1 student * 9 pets) = 0 + 4 + 4 + 18 + 8 + 9 = 43 pets
Next, we need to calculate the mean number of pets by taking the total number of pets and dividing it by the total number of students:
43 pets / 18 students = 2.39 pets
Therefore, the correct answer is:
A. 2.39