Complete the sci-fi author's manuscript by choosing the logically and grammatically correct continuation to avoid a "dangling participle."

Realizing the time machine was completely out of fuel, ____.

The correct answer is Professor Higgins frantically searched his pockets for spare plutonium.

When a sentence begins with a participle clause (Realizing...), the subject of the main clause must be the person or thing doing the action of the participle. Professor Higgins is the one who "realized," so he must be the subject of the main clause. The other options incorrectly make "a feeling," "the control panels," or "it" the subject, creating a dangling modifier.