Say someone is selling put options and their ONLY strategy when selecting which to trade is to see which will yield them X% over X time (disregard however stupid this may be). How do they calculate this? And how do they calculate this when using margin? For example, a trader is selecting puts to sell and wants to make 10% in a month or 20% over two months, so they select the puts to sell with a month or two month deadline. But how do they determine which strike price to select based on their desired return percentage over this trade's time? To make matters more complicated, say they are using margin at whatever ratio. Now how do they calculate which strike to buy? Thank you.