Which sentence contains unnecessary shift in verb tense?

a. if anyone knows the answer, she does.
b. as i came in the front door, eddie is going out the back door.
c. a row of ants had filed up the chair leg and was about to consume our lunch.
d. the barrier will drop down every time that a train approaches the crossing.

1. saved aronnax from drowning "an incident" 2. speed of the nautilus man-of-war 3. next to captain nemo conseil 4. electricity vigo bay 5. "a coral tomb" 20,000 leagues 6. the nautilus runs aground nemo's "thunderbolt" 7. episodes are connected by aronnax's quarters 8. captain nemo's "bank" cause 9. distance aronnax traveled on the nautilus "a fine death for a sailor" 10. captain nemo sinks for revenge 50 miles per hour