Answer:
a. credit to common stock for $625,000
Explanation:
When a company acquires more than 75% of holding in any company along with significant control then it is known as subsidiary. The company Is then able to record investment in subsidiary as debit balance in its statement of financial position. The cash consideration paid for acquiring the stock is recorded as investment in subsidiary. When the Pisa Company acquired Siena Company it has recorded the investment in Siena but when additional share are purchased Pisa will raise its stock capital.