Similarities Between Cells?
I would also go for d and g. All the others may vary. Strictly speaking, you may even have random, point mutations that have changed the genomic sequence between two given cells so even d and g might not be true in some cases.

I would also like to point out that recent evidence implies that differential expression of non coding, regulatory RNA molecules may play as, or even more, important a role as differential expression of proteins. See the ENCODE papers or here for a recent review.