Final answer:
Capital mobility and the international banking system are the two factors from the given options that can restrict specialization in the global economy, making D) Both A and B the correct answer.
Step-by-step explanation:
Specialization in the global economy can be restricted by numerous factors, but when considering the options provided, it is clear that capital mobility and the international banking system play significant roles. Capital mobility refers to the ease with which businesses and individuals can move their assets and investments across borders, influencing the global economy. The international banking system, through its regulations and financial controls, can affect the flow of capital and thus potentially restrict economic specialization.
Free trade, on the other hand, is generally a facilitator of specialization by allowing goods and services to be exchanged with fewer restrictions. While socialism and proposals like the Tobin tax might be seen as limiting factors, neither is explicitly listed in your question's options. Therefore, the correct answer here would be D) Both A and B, meaning both the international banking system and capital mobility can restrict specialization in the global economy.