If Sally only prefers A or B but not both, this could be an example of Independent Goods. These are goods that are neither complements nor substitutes, and changes with one good generally do not affect the other.
However, with the information about Sally's preferences, it sounds to me like it could also be an example of Cross-Category Substitute Goods. These are goods that can substitute (imperfectly) for one another. Consumers may find one good more satisfying than the other based on their individual preferences and utility function.
i.e. perhaps Sally wants a slice of pizza or Coke, and both cost \$1.
She prefers the taste of Coke so she generally chooses it, but one day the price of Coke goes up to \$2. She
may be satisfied to a similar degree purchasing pizza until the price
of Coke comes back down. On a different day, she may want to purchase 2
pizzas for the same amount as 1 Coke. There are many possible outcomes with
It's a little unusual and subjective, because both goods in the example are in consumable food/drink categories, but one good satisifies hunger and the other good satisfies thirst. Thus, it's hard to think of one being a replacement for the other unless one thinks of them both being sweets or snack items. (One common example uses a chocolate chip cookie and a chocolate chip granola bar in place of Coke and pizza.)
If this isn't the exact term you're looking for, I hope this helps you on the right track at least.