Question

read the claim.
animal testing is unnecessary in this century and should be banned.
read the counterclaim.
animal testing has led to important medical breakthroughs.
which is the best rebuttal to address the
counterclaim?
with modern technology, scientists can make
advances without involving the one hundred million
animals now used each year for animal testing.
with over one hundred years of successful animal
testing, it is obvious that the scientific community
must go on using animals to continue to be
successful.
while it is true that there have been successes in
the past with animal testing, that is not necessarily
an indicator of what will happen in the future.
while animals have been used for testing
throughout history, this does not mean that people
should just keep doing that because they are used to
it.

Explanation:

To rebut the counterclaim that animal testing led to medical breakthroughs (supporting its continuation), we need to show that past success doesn't guarantee future need, especially with modern tech. The first option points out modern tech allows advances without animal testing, directly addressing the counterclaim by showing an alternative to achieve medical progress, making it the best rebuttal. The other options either support animal testing (second) or focus on past - future irrelevance without offering an alternative (third) or address habit rather than necessity (fourth).

Answer:

A. With modern technology, scientists can make advances without involving the one hundred million animals now used each year for animal testing.