Given O below, If AB and BC are congruent, what is the measure of chord BC?

we know that
AB and BC are congruent
That means
[tex]AB=BC[/tex] ----> equation A
we have
[tex]AB=12.5\ units[/tex]
substitute in equation A
[tex]BC=12.5\ units[/tex]
therefore
the answer is the option B
[tex]12.5\ units[/tex]