I can't think of any good reason to prefer 28B over 29C if this is a 77W (773) flight you're talking about.

28B is bulkhead, but you can stretch your legs around the end of the dividing wall under the curtain, at an angle. But there is a (good) possibility of baby in bassinet in front of you, and fixed armrests both sides.

29C, OTOH, has unlimited legroom right in front of you and IIRC a fixed armrest only on one side. Potentially 2 people (29A, 29B) to climb over you, but they're likely to be doing so less often than a parent in 28A with a baby in the bassinet.