<p dir="ltr">The sentence in this question is a third conditional. <br></p><p dir="ltr"><span><span>The third conditional describes a situation that didn’t happen in the past and imagines the result of this situation. </span></span></p><p>The third conditional:<br></p><div dir="ltr" align="left"><table class="classic-table"><colgroup><col></colgroup><tbody><tr style=""><td><p dir="ltr"><span><span>If + S + past perfect, S + would/ could/ should/ might + have + past participle</span></span></p></td></tr></tbody></table></div><p><br></p><p>Thus, The sentence in this question becomes:<br></p><p>“If Mike had completed his master’s degree, he would have gotten a better job.” </p><p dir="ltr"><span><span>In a third conditional sentence, the subordinating conjunction “If” can be omitted, but this if-clause has to become an inverted sentence. So, this if-clause becomes </span></span>“Had Mike completed his master’s degree.” </p><p dir="ltr"><span><span>The correct answer is (A) Had. </span></span></p><p dir="ltr">The sentence in this question is:</p><p dir="ltr">Had Mike completed his master’s degree, he would have gotten a better job.</p>