<p>Southwest Airlines requested that all baggage <strong>be kept</strong> in the overhead compartments.</p>
<p>The correct answer is (A) <strong>be kept</strong>.</p>
<p>In this sentence, the verb "be kept" is in the subjunctive mood. The subjunctive mood is used to express a command, a request, a suggestion, or a hypothetical situation. In this case, Southwest Airlines is making a request for all baggage to be kept in the overhead compartments.</p>
<p>In English grammar, the subjunctive mood is formed using the base form of the verb, which is the infinitive without "to." In this case, the base form of the verb "keep" is "be kept."</p>
<p>Options (B), (C), and (D) are incorrect because they do not use the subjunctive mood correctly. Option (B) uses the indicative mood ("is kept") instead of the subjunctive mood. Option (C) uses the plural form of the verb ("are kept") instead of the singular form. Option (D) uses the base form of the verb ("keep") without the subjunctive mood.</p>