Suppose there is a simple index of two stocks - stock A and stock B. Stock A
opens on Monday with 10,000 shares at $4.25 per share. Stock B opens on
Monday with 5000 shares at $6.75 per share. Stock A opens on Tuesday at
$4.50 per share, and stock B opens on Tuesday at $6.35 per share. Both
stocks have the same number of shares that they opened with on Monday.
What is the rate of change of this simple index over 1 day?

A. -0.9%
B. 0.9%
C. -0.7%
D. 0.7%