Choose the correct variant to fill in the blank Communication systems allowed managers __ staff effectively. a. to direct b. direction c. direct d. directing

The correct answer is a. to direct.<br /><br />In this sentence, the blank requires an infinitive verb form to complete the phrase "allowed managers __ staff effectively." The correct option is "to direct," which means to guide or control the actions of others. The other options, "direction," "direct," and "directing," do not fit grammatically or contextually in the sentence.