Which statement is true about stem-changing verbs in the preterite?
a) Only -ir stem-changers show a stem-change in the preterite.
b) All stem-changing verbs show a stem-change in the preterite.
c) No stem-changing verbs show a stem-change in the preterite.
d) Stem-changing verbs in the preterite normally change o —> ue or e —> ie.