It is difficult to say how accurate these devices are when used at home because most research on their effectiveness has been conducted in a laboratory setting.
<h3>What is a sentence?</h3>
A sentence can be defined as a group of words that is typically made up of a subject and predicate, which are used by a writer to convey a logical information to his or her audience (readers).
In this scenario, a sentence which best accomplishes this goal is re-writing the given sentence as "It is difficult to say how accurate these devices are when used at home because most research on their effectiveness has been conducted in a laboratory setting" because the important information are still present in the new sentence.
Read more on a sentence here: brainly.com/question/985037
What are the choices you have to choose from?
I'm pretty certain that it's a or b. C and D would be something that a surgean would wonder. Although, im most certain that it's B. Scientists are always asking how or about the causes of something