Answer: B) If two lines are parallel, then the lines lie in the same plane.
Explanation: A conditional sentence is a type of sentence that states a situation and the outcome of that situation (condition) occurring. From the two given options, the correct one is the corresponding to option B, because the fact that two lines are in the same plane, doesn't necessarily mean that the lines are parallel (so option A isn't always true), but if two lines are parallel, they definetly lie in the same plane (option B is always true).
