Step 1: Understanding capital in the economy.
In economics, capital refers to physical assets that are used to produce goods and services. These include infrastructure such as roads, buildings, and other public facilities that aid in economic activities.
Step 2: Analyzing the options.
(A) Building: Correct. Buildings are considered capital in the economy as they are used for commercial or residential purposes, facilitating production and services.
(B) Office place: Correct. Office places are capital assets that are used for business activities and services.
(C) Road, bridge, airport: Correct. These are public infrastructure assets that support economic activity by providing transportation and connectivity.
(D) All of these: Correct. All of the options listed are forms of capital that contribute to the economy.
Step 3: Conclusion.
The correct answer is (D) All of these, as all listed options represent forms of capital in the economy.