The given options are ‘between’ and ‘From’. ‘Between’ denotes time sometime during two given ends. For example : You can see me between 8 a.m. and 10 a. m. It means you can come at any time between these two limits. But ‘From’ denotes duration of time stretching from one point to other point. As in the given sentence the doctor is there all the time during the stretch of 9 a.m. to 1 p.m. These two words often create confusion particularly due to use of such words in our vernacular languages. So correct option is ‘from’.