If the tangent at point $(1, 2)$ on the curve $y = ax^2 + bx + \frac{7}{2}$ is parallel to the normal at point $(-2, 2)$ on the curve $y = x^2 + 6x + 10$,then:

• A
  $a = 1$
• B
  $a = -1$
• C
  $b = -\frac{15}{2}$
• D
  $b = \frac{5}{2}$