Entries #25 and #26 were submitted just in case you were open to colors other than primaries. Yellow does not show up well on a white background so the best option is for a red/blue combo. Red and blue together tend to cause a slight conflict in the eye, even if only subconsciously to the viewer, which makes the design less pleasing. Just a word of advice from a designers perspective.
The blue/silver combo has more of a technological/mechanical feel to it and the blue/orange combo has a more modern color-scheme.
Please let me know if you would like any changes.
Thank You.
~IB