Final answer:
In doll collecting, 'M.I.B.' stands for 'Mint in Box,' meaning the doll is in its original unopened packaging and untouched condition.
Step-by-step explanation:
In doll collecting, M.I.B. stands for Mint in Box. This term indicates that a doll is in its original packaging and has not been removed or played with, therefore retaining its full value as a collectible. Collectors value the condition of dolls highly, and having the original box often significantly increases a doll's worth and appeal to collectors. Mint in Box dolls are considered to be in the best possible condition, similar to how they would have appeared at the time they were first sold.