Mort and Velma Are Twins, Born at the Same Time

Multiple Choice

Mort and Velma are twins, born at the same time on Earth. Velma is taken on a long trip into outer space, at a speed close to lightspeed, and returns to Earth. When she returns,

A) Mort observes that he is older than Velma, and Velma observes that she is older than Mort.
B) Mort observes that he is younger than Velma, but Velma will observe that she is younger than Mort.
C) Mort and Velma both observe that Mort is older than Velma.
D) Mort and Velma observe that they have aged equally.
E) Mort and Velma both observe that Velma is older than Mort.