What is the fundamental accounting equation?

Assets = Liabilities + Capital

The correct answer is option 4- Assets = Liabilities + Capital.

Dual aspect is the foundation or basic principle of accounting. It provides the very basis for recording business transactions into the book of accounts. This concept states that every transaction has a dual or two-fold effect and should therefore be recorded at two places. In other words, at least two accounts will be involved in recording a transaction. The duality principle is commonly expressed in terms of fundamental Accounting Equation, which is as follows :
Assets = Liabilities + Capital.
In other words, the equation states that the assets of a business are always equal to the claims of owners and the outsiders. The claims also called equity of owners is termed as Capital(owners’ equity) and that of outsiders, as Liabilities(creditors equity). The two-fold effect of each transaction affects in such a manner that the equality of both sides of equation is maintained.