Task: Question Answering
Input (English): Question: It is very common the use of rotary valves of 6 doors or routes, alternately switchable, for the injection of samples in liquid chromatography of high resolution. Which of the following answers is correct? 
 Options:  <1> In the injection position, the mobile phase flow is maintained towards the column without passing through the loop. <2> In the loading position, the loop in charge of housing the sample remains open to the atmosphere whereby the sample can be deposited by means of a syringe. <3> In the loading position, the mobile phase flow is maintained towards the column by previously passing through the loop. <4> In the loading position, the sample is inserted into the column without disturbing the moving phase step towards the loop. <5> In the injection position, the entire internal volume of the loop is directed to the waste while the mobile phase carries the sample.
Output (English): 2