A farmer who grows blackberries has found his harvest to be lower than usual. He suspects that some animals are eating the berries before he can pick them. The farmer thinks it may be either birds (landing on the bushes to feast on berries) or rodents (climbing the bushes from below to munch on berries). He decides to first test the hypothesis that birds are eating his berries, and consults with a local expert on how best to prevent the birds from eating berries. He has eight fields with 10 rows of berry bushes in each field. In one of his fields (depicted below, as viewed from above), he covers half of the rows with nets that will prevent birds from landing on the bushes, and leaves the other half uncovered. Over the course of 8 weeks, he counts the berries harvested from each row of bushes in the test field.

What are the experimental units in his experiment? Asked another way: If you had to write a value for "n", the number of units studied, which would you use for "n"?

a.
The blackberries

b.
The blackberry bushes

c.
The rows of bushes

d.
The fields