The correct answer is: E. No correction required.
The sentence “Our departure from this place now depends on their coming here” is grammatically correct. The verb “depends” takes a gerund phrase as its object, so the correct answer must be a gerund phrase. The gerund phrase “their coming here” is a noun phrase that functions as the object of the verb “depends.” The gerund phrase is composed of the gerund “coming” and the object pronoun “them.” The gerund “coming” is the present participle of the verb “to come,” and the object pronoun “them” refers to the subject of the sentence, “our departure.”
The other options are incorrect because they are not gerund phrases. Option A, “they come,” is a simple sentence with a subject (“they”) and a verb (“come”). Option B, “them coming,” is a gerund phrase, but it is not the object of the verb “depends.” Option C, “they coming,” is a gerund phrase, but it is not a noun phrase. Option D, “their’s coming,” is not a grammatically correct sentence.