Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

[EX Q]: Vaginal microbicides for the prevention of HIV transmission may be an important option for protecting women from infection. Incorporation of dapivirine, a lead candidate nonnucleoside reverse transcriptase inhibitor, into intravaginal rings (IVRs) for sustained mucosal delivery may increase microbicide product adherence and efficacy compared with conventional vaginal formulations. Twenty-four healthy HIV-negative women 18-35 years of age were randomly assigned (1:1:1) to dapivirine matrix IVR, dapivirine reservoir IVR, or placebo IVR. Dapivirine concentrations were measured in plasma and vaginal fluid samples collected at sequential time points over the 33-day study period (28 days of IVR use, 5 days of follow-up). Safety was assessed by pelvic/colposcopic examinations, clinical laboratory tests, and adverse events. Both IVR types were safe and well tolerated with similar adverse events observed in the placebo and dapivirine groups. Dapivirine from both IVR types was successfully distributed throughout the lower genital tract at concentrations over 4 logs greater than the EC50 against wild-type HIV-1 (LAI) in MT4 cells. Maximum concentration (Cmax) and area under the concentration-time curve (AUC) values were significantly higher with the matrix than reservoir IVR. Mean plasma concentrations of dapivirine were <2 ng/mL. These findings suggest that IVR delivery of microbicides is a viable option meriting further study.
[EX A]: Which infection can be prevented with Dapivirine?

[EX Q]: On at least one occasion they succeeded and formed the Kingdom of Kurdistan, which lasted from September 1922 until July 1924.
[EX A]: Which year did Kingdom of Kurdistan end?

[EX Q]: In America, when the eighth graders leave the middle school, they are often worried about moving to the high school. It is a hard time for them, but it can be an exciting one as well. To make it easier, students need to get familiar with their school. Even though they've done this already in the middle school, it's still important to find where their classrooms are. Most schools take students to the high school for a visit at the end of their eighth grade year. And, most schools also have a freshman speech for parents and students before the first year begins. Sometimes the main office will give away a map of the school. This can help students and parents to find different places in the school. One way to know your high school more and make new friends is to join a club or play a sport. Schools often offer chances to join different clubs and sports. Fall activities begin in August before the first day of school. If you are not interested in sports, there are clubs for any interest, such as drama, dance, chess, photography, community service, etc. These clubs allow students from different grades. By joining an activity, students can find new friendships, not to mention improving their chances in future college applications . The school office will have a list of activities offered at the school and information on how to join them. What's more, to have a great start to a high school year, students can write down some of their worries, and ask for help from teachers and school workers.
[EX A]:
When do many schools take students to visit their new high school?