Which backbox is right for my 172 Cup?

[STCaulkin]

Hello, I have a 172 Cup '53 and have just ordered a centre section and need a backbox too.

Please can someone advise me which one will fit my Cup - if it is any different than a 172. I no nothing about cars so please explain simply although should be fairly straightforward. I believe the one I have looks like option C from a quick peek underneath. Just don't want to order the wrong one!


Option A
http://www.ebay.co.uk/itm/Renault-C...o|Cars+Type:2.0+16V+Sport&hash=item565ae6478d

Option B
http://www.ebay.co.uk/itm/Renault-C...o|Cars+Type:2.0+16V+Sport&hash=item4616b9cea2

Option C
http://www.ebay.co.uk/itm/EXRN6012-...arts_Vehicles_CarParts_SM&hash=item43ada10de2

Thanks in advance