Given the theorem: There is no largest negative real number, which of the following is the first step if a proof by contradiction is used? O Assume there is a smallest positive real number called r. O Assume there is a largest negative real number called r. O Sincer is positive, r/2 is also positive. Since r is positive, r > (r/2). O Sincer is negative, 2*r is also negative. Since r is negative, (2 * r)