I have a very specific task, but can't handle it. I am not a programmer and totally n00b on bash scritps. So the question is, how to create a cron job like this:

Script A.sh could be called at any time by hands, and it should create cron job to run script B.sh once at the nearest time point. For example I will have 4 time points: 10.00pm, 10.15pm, 10.30pm, 10.45pm. So if trigger a script A.sh at 10.07pm it should creat cron job to run ONCE script B.sh at 10.15h, because 10.15h is the nearest time point in future.

Is it possible? How can I write such script A.sh? I use Centos 6

It is very important and urgent for me. Thank you very much.