Answer: C)
Step-by-step explanation:
The correct and most meaningful answer is C).
When it comes to the rules of parallelism, the most important thing referring to the parallelism is that in the sentence, the similar elements should be expressed in the same or parallel grammatical form.
In this case, we can see that in the usage of ''taught'' and ''spoke'' in the sentence which are the words written in the past tense.