Final answer:
The correct answer is 'Fewer'. The teacher instructed the students to take out no fewer than two pencils from their backpacks.
Step-by-step explanation:
The correct answer for the question is a) Fewer.
Fewer is the correct word to use because the teacher is referring to the number of pencils, which are countable items. In this case, the teacher wants the students to take out no fewer than two pencils, meaning they should take out at least two pencils.
An example of using fewer in a sentence would be: "I have fewer pencils in my backpack than my friend."