Answer:
<em>The principal parts of a </em><em>B. regular</em><em> verb are formed by adding -ed, -d, or -t to the present part. </em>
Explanation:
An English verb can be either <u>regular</u> or <u>irregular</u>, according to their formation in the simple past and in the past participle. <u>Regular verbs</u> are formed by adding -ed, -d, or -to to the infinitive, while <u>irregular verbs</u> can end in a wide variety of ways with no consistent pattern.
Example of regular verb: start-started.
Example of irregular verb: feel-felt.