PUSH is painted on a shop's glass door so that it reads correctly from the street. A customer inside sees it from behind, exactly like a mirror image. Which panel shows what the customer sees?

Seen from behind, the word is reversed left-to-right: the letters run H S U P and P and S face the other way, while U and H are symmetric: (a). (b) is the street view, (c) reverses the order but keeps P and S normal, and (d) is upside down.