Meiosis and crossing over Q pls help :)

Would anyone mind taking a look at Q1b)
on the
June 2018 QP - Paper 2 Edexcel (A) Biology AS-level
and explaining to me why the answer is C. I really dont understand it thank uuu in advance if you have a look!!!! I would really appreciate any help

I think it’s because if crossing over occurs, the bottom two sections of the chromosomes switch so for the chromosome with gene a on one and gene A on the other, since the top two sections are the same, if they switch it makes no difference so you’re left with the same thing. For the second pair of chromosomes, when they switch instead of having B+C on one chromatid and b+c on the other, the bottom two sections would switch so you’d have B+c on one and b+C on the other if that makes sense. Then it’s easy to work out which one is the only one which could be present since if you ignore the a/A bit, then the first and second one have BC, and the last one has bc and since crossing over has occurred you know none of these can be true since it can only be Bc or bC. I tried to explain it in a drawing since my wording isn’t the best x

OMG I GET IT NOW THANK YOU SO MUCH!! I really really appreciate it and am so grateful thank uuu