Basic Trig Question - In the right angled triangle ABC, where AB is the hypotenuse, the sine of angle ABC =

I was doing one of those mental aptitude tests for a interview and I came across a question which I believe has the wrong answer but need to verify if I am right.

In the right angled triangle ABC, where AB is the hypotenuse, the sine of angle ABC =

Options are -

A: BC/AB
B: AB/BC
C: AC/AB
D: BC/AC
E: AC/BC

In my view the answer is A. But then again it could also be C depending on which angle is used as a reference. I just don't think the question is worded properly.

The triangle hypotenuse is AB so angle ACB is the right angle.
The side AC is opposite ABC so
The sine of ABC is AC/AB
So C. AC/AB is the answer

The question is worded correctly.
The only correct answer is AC/AB