Hi, <br/><br/>Which one of the following sentences is correct and natural, please?<br/><br/><b>a)</b>. <i>Can you <u>fill the blank with</u> the appropriate preposition. </i><br/><br/><b>b)</b>. <i>Can you <u>fill in the blank with</u> the appropriate preposition?</i><br/><br/><b>c)</b>. <i>Can you <u>fill in the blank</u> appropriate preposition?</i><br/><br/>Thank you.