how can i change templates depending on the taxonomy

Hi,
I want to change the template of a taxonomy and its children.
I have several categories, I need to change templates for a category and its children.

<?php if (is_category(‘Category A’)) : ?>
<p>This is the text to describe category A</p>
<?php elseif (is_category(‘Category B’)) : ?>
<p>This is the text to describe category B</p>
<?php else : ?>
<p>This is some generic text to describe all other category pages,
I could be left blank</p>
<?php endif; ?>

I tried this code but

it doesn’t work.

Thank you