What is wood? (Multiple Choice)

What is wood?
  a. secondary xylem that has accumulated outside a cylinder of vascular cambium
  b. secondary xylem that has accumulated inside a cylinder of vascular cambium
  c. primary xylem that has accumulated outside a cylinder of vascular cambium
  d. primary xylem that has accumulated inside a cylinder of vascular cambium
  e. vascular cambium cells

Question 2

Cylindrical layers of meristem that run lengthwise through shoots and roots, and allow for thickening, are called ____.
  a. lateral meristems
  b. apical meristems
  c. ground meristem
  d. Procambium
  e. Protoderm