JD84

Hi there, I got the below fault code ( PO136) when i connected the OBD - Apparently there are 3 types of Oxygen sensors - does anyone know which is the right one? -Zirconia -Wideband -Titania Also for the above 3 would it be positioned - Sensor 1 in front of the catalytic converter - Sensor 2 located behind and beneath the catalytic converter also does anyone know the part number? Thanks