Some say the best time to get vitamin d from sunlight is from 7 to 9...some others say that the best time to get vitamin d is from 10 to 3 ....which one of this is true for getting the best vitamin d from sunlight?how much does one get in 15 minutes?

This will depend on exactly where you live and at what altitude and how much smog you have and time of year/angle of sun.. Some parts of India are very high and others at sea level..Need more info I would check with local health dept. I remember from Biochem that if a chicken walks 100 yards in the sun at a regular pace on a clear day in summer it will get enough sunshine to sunlight for the day