Final answer:
Lucy can leave home at 11:20 am to arrive at Martha's house in time for lunch.
Step-by-step explanation:
To determine the latest time Lucy can leave home to arrive at Martha's house in time for lunch, we need to consider the travel time from Lowtown to Midtown and the time needed for lunch. Let's say Lucy needs 30 minutes to travel from Lowtown to Midtown. If Martha's lunchtime is at 12:00 pm, Lucy needs to arrive a few minutes earlier to give them time to settle in and start eating. Let's say Lucy wants to arrive at least 10 minutes before Martha's lunchtime, so she doesn't rush. Therefore, the latest time Lucy can leave home is 11:20 am. This means that option c, 10:35 am, is the incorrect answer choice.