Aguitar player shortens the length of a guitar's vibrating string by pressing the string straight down onto a fret. the guitar then emits a higher-pitched note, because

a) the string's tension has been dramatically increased.
b) the string can vibrate with a much larger amplitude.
c) the string vibrates at a higher frequency

Will mark determine whether the conjecture is true or false. give a counterexample for any false conjecture. given: points r, s, and t conjecture: r, s, and t are coplanar. a) false; the points do not have to be in a straight line. b) true c) false; the points to not have to form right angles. d) false; one point may not be between the other two.