My daughter has a 99 Civic LX, California Model (LEV I think)?

Does this car have one or two O2 sensors?

She got a CEL, Autozone says their scanner cannot differentiate between
a front or a rear O2 sensor failure.

The front sesnor is about a year old.

Are there front and rear sensors, or is the Auto Zone dude all wet?

The rear sensor price is about $250 (if there is such a thing).

Tom