I will be travelling to Canada (from Bangladesh) on December through Istanbul. In the online e-visa page for transit visa, i could only find USA, Shengen countries, Ireland and UK. Does that mean I will not be granted an online Visa?
If you want/need to enter Turkey (for example to pick up luggage - this is if the trip is not in one booking - or to see Istanbul for a while), you will need a transit visa from a Turkish embassy.
Otherwise you need no visa at all.
You can apply for an e-visa and get it, by marking all the checkboxes, but if you don't actually fulfil the requirements, it will be invalid.
But like I said, if you just transit there and your trip is in a single booking, you do not need a visa