In 1881, French chemist Camille Faure redesigned the rechargeable lead-acid battery. Faure’s design greatly

Choice D is the best answer. Faure redesigned the battery in 1881, and the original battery was invented “fifteen years earlier.” Notice that this is the only choice in the past tense. To indie that a past occurrence took place before another past occurrence, we need to use “had” + the past tense form of the verb. This is called the “past perfect” tense.

Choice A is incorrect. This choice creates a tense error. Planté invented the original battery in the past, so we shouldn’t use the present tense “is inventing.” Choice B is incorrect. This choice creates a tense error. Planté invented the original battery in the past, so we shouldn’t use the future tense “will invent.” Choice C is incorrect. This choice creates a tense error. Planté invented the original battery in the past, so we shouldn’t use the present tense “invents.”