Let's say for this scenario:<br/><br/>It is 9:45 a.m and Mr A asks Mr B about a department store.<br/><br/>A: What time does the department store open?<br/><br/>B: It opens at 10 a.m.<br/><br/>A: Until what time<b> will it be/ is it</b> open?<br/><br/>Should it be 'will it be' or 'is it' for this question?<br/><br/>Thanks.