Three parallel lines x, y and z are cut by two transversals m and n. Transversal m cuts the lines, x, y, z at P, Q, R respectively, and transversal n cuts the lines x, y, z at L, M, N respectively. If PQ = 3 cm, QR = 9 cm and MN = 10.5cm, then what is the length of LM?

• A. 3 cm
• B. 3.5 cm
• C. 4 cm
• D. 4.5 cm