Benzophenone reacts with phenylmagnesium bromide in ether solution to make triphenylmethanol after acid workup. Which of the following experimental mistakes will decrease the effectiveness of a Grignard reaction? Select all answers that apply.

a. The magnesium ribbon is insoluble in ether.
b. The glassware was not dried before use.
c. The fume hood was too cold.
d. The magnesium ribbon was not wiped clean before use.