Which of these has the largest value?(A) 1+22\dfrac{1+2}{2}21+2 (B) 1+2+33\dfrac{1+2+3}{3}31+2+3 (C) 1+2+3+44\dfrac{1+2+3+4}{4}41+2+3+4 (D) 1+2+3+4+55\dfrac{1+2+3+4+5}{5}51+2+3+4+5 (E) 1+2+3+4+5+66\dfrac{1+2+3+4+5+6}{6}61+2+3+4+5+6