A binary call option is the correct answer. This type of option is structured in a way that the payoff is a fixed amount of money if either (I) a specified price is reached/exceeded at the time of expiration or (II) the option is simply in-the-money at the time of expiration. In this case, the investor will receive a payoff of $100 if the stock price reaches $71 at the time of expiration, which is a characteristic of a binary call option. Binary options are also known as all-or-nothing options because they either pay the full amount or nothing at all. This type of option is often used when an investor believes that the price of an underlying asset will reach a certain level in the future, but is unsure about the sustainability of the price increase.

Choice A is incorrect. A European call option allows the holder to buy the underlying asset at a specified price within a specific time period, but only on the expiration date. However, in this scenario, the payout is not dependent on the difference between the stock price and strike price at expiration but rather it's fixed at $100 if stock price hits $71 which aligns with characteristics of a binary call option.

Choice B is incorrect. An American call option also allows its holder to buy an underlying asset at a specified price before or on its expiration date. But similar to European options, their payoff depends on difference between stock and strike prices which doesn't match with given scenario.

Choice D is incorrect. LEAPS (Long-term Equity Anticipation Securities) are long-dated options that have an expiry period longer than one year. The type of payoff structure described in this question does not relate to whether an option has long or short term maturity but rather it's about how payoff is calculated at expiry which makes LEAPS irrelevant here.