That is probably a rather simple question but I got confused and would be very thankful for help. Imagine we are in 2015 and have an option that expires in either 2016, 2017, 2018, 2019, 2020 or 2021. We are given the volatilies for t_1 = 31,84%, t_2 = 27,45%, t_3 = 26, 64%, t_4 = 26,27%, t_5 = 26,16% and t_6 = 26,25%. I have to value the option for each expire date and I think I need to use forward volatilities. But can someone tell me what I exactly need to do to price them? What vola do I use for the option that expires in 2016, 2017, ...?
Thank you so much!