As I recall (and it’s been 42 years) this little item from can 4 was the most popular C-ration. It’s the fruitcake. When you got one of these you felt blessed by the gods.
For more C-ration memories (if you’re so inclined) go here. Not only a photo of the famous P-38 (not the WW2 fighter but the 1969 can opener) but also the small four-packs of Marlboros and matches from those pre-PC days.
THE TEXAS SCRIBBLER 
I may have mentioned this before, after all, I’m an old man, but…
By the time I was short, I had grown to loved ham & eggs, chopped, water added. Other guys would shitcan them, and I scarfed them up. When we ran out of chow, I still had plenty of ham & eggs, etc., etc.
And I got to where I liked them Chest-busters, and Luckies, and Pall Malls (Chestbusters being Chesterfields, natch), I was even known to try rolling up chewing tobacco in C-rat asswipe, when times were hard.
The only one I ever heard was hated (I never tried it) was ham and lima beans. Just the thought of the combined colors is nauseating.
I smoked Camels in those days, until I learned that Salems were cash-money with the Vietnamese and so I switched.
I’ve tried the new field rations. They don’t seem like much of an improvement and, of course, there aren’t any cigarettes.