In a rectangular coordinate system, what is the area of a rhombus whose vertices have the coordinates (0, 3.5), (10, 0), (0, -3.5), (-10, 0)?
Choose the most appropriate option:
A) 56	B) 88	C) 70	D) 116	E) 120

Rationale: "area of rhombus = 1 / 2 * d 1 * d 2 length of 1 st diagonal = 10 + 10 = 20 length of 2 nd diagonal = 3.5 + 3.5 = 7 area = 1 / 2 * 20 * 7 = 70 c is the answer"
Answer: C