Which of the statements below is true about the following sentence: it was the night before christmas and all through the house, not a creature was stirring, not even a mouse. a. both "was" and "was stirring" are past tense. b. "was" is past tense, but "was stirring" is present continuous. c. "was" is past continuous, but "was stirring" is past perfect. d. both "was" and "was stirring" refer to the past, but when placed together in the same sentence, two past tense verbs cancel each other out and the sentence becomes present tense.