Which sentence uses consistent verb tense?

Which sentence uses consistent verb tense?

The guide at the museum walked the group around the exhibit as she explains the significance of the object.

Going for a walk on a sunny day relieves stress and encouraged good blood flow through the body.

The trains pulled into the station and all of the passengers get out.

I left the house without an umbrella and regretted it for the rest of the day.

The guide at the museum walked the group around the exhibit as she explained the significance of the object.