Kill me now...

I stepped on the scale at the gym this morning after not having been to the gym in a month and have discovered shamefacedly that I've gained back all the weight (keep in mind we're only talking like 10 lbs not 100 or anything too crazy, I don't diet and still eat tons of crap foods which does not assist the weight loss) I lost in 1 year of working out regularly... in 1 little month.
Possible answers:

A - I gained back all the weight I've lost because I've sat on my ass every morning instead of working out. :( (Not my favorite one)
B - Muscle weighs more than fat so this is all muscle built. (Most delusional)
C - The scale at the gym is broken (My favorite one)
D - The new pants still fit so I really couldn't have gained that much weight back. (Except the possibility exists that I have always bought my pants too big because I like them baggy and comfy and not circa 1980 Jordaches... although that actually still supports the argument because new pants are comfy and do not require me lying on my bed doing the wiggle pant dance)
E - The bottle of water and banana I consumed before the gym.
F - Combination of all above factors. (Most likely)