Valuing an option that is issued today, exercisable after 2 years and expires 3 years from today

Hi All, 

I was wondering what the best approach would be for valuing a call option that is issued today, expires in 3 years from today but cannot be exercised until at least 2 years from today. To be clear, in can be exercised at anytime after 2 years from being issued. 

We're assuming the stock doesn't pay a dividend.

Would a Binomial tree be best or would BSM be a close enough to be a proxy?

If the Binomial tree, how would you set it up? i.e would you assume it's exercisable at only years 2 and 3 so simplicity? or set it up for daily movements after 2 years to expiry?

Thanks