Answer:
The cost basis for the land is equal under both options.
Step-by-step explanation:
If Taylor pays Ella $150,000 in cash and assumes the mortgage of $100,000, the cost basis of the land will be $250,000 (= $150,000 + $100,000). If he decides to pay Ella the full amount of $250,000, that will also be the cost basis of the land.
The only real difference is that if Taylor decides to assume the mortgage, he will need a smaller initial cash flow ($150,000).