A Portfolio Is a Collection of Investments Made by Individuals

A portfolio is a collection of investments made by individuals or institutions. The market portfolio then is:

A) A collection of investments into a specific market.
B) A collection of all securities where the amount invested in each security is proportional to its relative market value.
C) A collection of all securities available in a specific market and the amount invested is the same for every security.
D) A collection of all investments in a whole economy.