Oxygen sensor code

I am getting a P0157 error code on my 1996 5.7 Chevy Suburban. It indicates that bank 2 sensor 2 has a problem. What O2 sensor is that?

From looking at the books, B2S2 is a downstream sensor, which is the same for left and right. Bank one is always the side that has the number one cylinder on it, and bank two is the opposite side.