Directions: Fill in the blank:

The President of the United States, accompanied by his advisors, _______ en route to Europe.

The correct answer is 'was.'

Key Points

• In the given sentence, the noun subject 'President' is a singular subject.
• We know that a singular subject always takes a singular verb.
• From the given options, only the third option 'was' is the first and third-person singular past verb.
   

Hence, the correct answer is option 3.

Complete Sentence: The President of the United States, accompanied by his advisors, was en route to Europe.

Additional Information

• Subjects and verbs must agree with one another in number (singular or plural).
• If a subject is singular, its verb must also be singular; if a subject is a plural, its verb must also be plural.