challenge: What is a characteristic of Weak, Class I verbs in Middle High German?
  
  A. They are the most common type of weak verb
  B. They exhibit no changes in the stem vowels in the present and preterite
  C. They have the same stem vowel in the present and preterite
  D. They are the descendants of a group of Old High German verbs ending in '-jan'
  Answer: 