Answer: The sentence that contains a dangling modifier is B. On the way to his inauguration, Washington’s boat took him up the Hudson River.
Explanation: A dangling modifier is a word or phrase which intends to modify a word or phrase that is not present in the sentence. In other words, a sentence contains a dangling modifier when the target word is missing. For instance, in sentence B., the phrase "On the way to his inauguration" is a dangling modifier since it is modifying a word that has not been clearly stated in the sentence: Washington. Therefore, the subject of this sentence should be "Washington" instead of "Washington's boat".