Which of the following assessment findings during a clinical breast examination (CBE) would necessitate referral for further investigation?
A) A mobile, well-defined, non-tender, firm, round mass in the upper outer quadrant of the left breast
B) An oval, rubbery, mobile mass in the lower inner quadrant of the right breast
C) A non-painful, movable, firm lump in the upper inner quadrant of the left breast
D) A tender, warm, and non-mobile mass in the lower outer quadrant of the right breast