These Masters & Slaves are sold as a pair.
0048A = 0048C & 0048B = 0048D. Either combination will work correctly.
Please carefully check the Manufacturers Part Number (MPN) and all other details.
The picture & model number alone does not guarantee compatibility. It is quite common for the same model to have different parts fitted so please purchase by MPN / Part Number if possible. Further information is available in Part Numbering Help.