Question

One of the key assumptions about preferences is that consumption bundles with more of both goods are preferred to those with less of both. Assuming people are rational, if two indifference curves cross, they must not belong to the same person. True, False or Uncertain

Answer 1

One of the key assumptions about preferences is that consumption bundles with more of both goods are preferred to those with less of both. Assuming people are rational, then two indifference curves can't cross, if they belong to the same person, because different indifferent curves are at the different levels and cross with different budget constraints.
So, the statement is True.