Which sentence requires semicolons instead of commas?(1 point)

On our summer road trip, we will travel by car, train, and bus to three different states.
On our summer road trip, we will travel by car, train, and bus to three different states.

On our summer road trip, we will travel to Pennsylvania, Maryland, and Delaware.
On our summer road trip, we will travel to Pennsylvania, Maryland, and Delaware.

This summer, we are going on a road trip to Philadelphia, Pennsylvania, Baltimore, Maryland, and Rehoboth Beach, Delaware.
This summer, we are going on a road trip to Philadelphia, Pennsylvania, Baltimore, Maryland, and Rehoboth Beach, Delaware.

This summer, we are going on a road trip to the cities of Philadelphia, Baltimore, and Rehoboth Beach.

The sentence that requires semicolons instead of commas is:

This summer, we are going on a road trip to Philadelphia, Pennsylvania, Baltimore, Maryland, and Rehoboth Beach, Delaware.

Explanation:
In general, semicolons are used to separate items in a list when those items already contain commas. In the sentence provided, the list of cities includes commas within each city name (e.g. Philadelphia, Pennsylvania, Baltimore, Maryland) which makes it necessary to use semicolons instead of commas to clearly separate the different cities. Therefore, the correct sentence would be:

This summer, we are going on a road trip to Philadelphia, Pennsylvania; Baltimore, Maryland; and Rehoboth Beach, Delaware.