TOEIC・English Undergraduate about 3 yearsago

この文に出て来るthat は前のits customers だけじゃなくて文全体を修飾してるんですよね？

87. OnePhone is getting ready to send a software update to its display signal customers that will allow the device to more --- reception. (A) accurate (B) accurately (C) accuracy (D) accuracies svitsolbini od 1 10