What does the notation $f\left(x\right)$ represent in the context of functions relating $x$ and $y$?

• A. A product formed by multiplying the symbol $f$ by the variable $x$, yielding a combined algebraic expression that may represent an area or a compound quantity
• B. The output $y$ corresponding to the input $x$
• C. The instantaneous rate of change of $y$ with respect to $x$ at the point $x$
• D. A new independent variable named $f$, unrelated to the original input $x$, denoting a separate coordinate

Answer: (B)