Step 1: Understanding purchasing power.
The ability to purchase goods is derived from income. Income refers to the money received, typically on a regular basis, for work or through investments, which allows a person to buy goods and services.
Step 2: Analyzing the options.
(A) From capital: While capital can help generate income, it does not directly provide the ability to purchase goods unless it is used to produce income.
(B) From income: Correct. Income is the primary source through which people gain the ability to purchase goods.
(C) From land: Land may be a source of wealth, but it does not directly provide the purchasing power unless it generates income.
(D) None of these: This is incorrect, as the correct answer is (B) From income.
Step 3: Conclusion.
The correct answer is (B) From income, as income enables individuals to purchase goods and services.