Answer: B. The sides of an Egyptian pyramid are almost perfectly equal.
Step-by-step explanation: Subject-verb agreement means the subject and verb must have the same number (both singular or both plural). From the given sentences, the one that has a correct subject-verb agreement is the corresponding to option B: The sides of an Egyptian pyramid are almost perfectly equal because the subject (the sides) and the verb (are) are both in plural form. The other sentences have errors in the number of the verbs.