Answer:
D) +25%.
Explanation:
If A offers 1/2 a share per 1 share of B, it means that the value of B's shares will increase from $20 to $25 (= $50 x 1/2). This $5 increase represents a 25% increase in wealth {= [($25 - $20) / $20] x 100}.
The price of the stock represents the wealth of the stockholders, since a stockholder that had 100 shares previously owned $2,000 in stocks, but as the price increases, the stockholder's wealth increases to $2,500.