Step 1: Understand the term.
A cell reference is the unique address used to identify a particular cell in a worksheet.
It consists of
\[
\boxed{\text{Column Letter + Row Number}}
\]
For example,
\[
A1,\; C5,\; D12,\; AA20
\]
are cell references.
Step 2: Understand its use.
Cell references are used in formulas and functions to perform calculations.
Example:
\[
=A1+B1
\]
adds the values stored in cells A1 and B1.
Step 3: Analyse the options.
• (A) Incorrect. Font size is a formatting property.
• (B) Correct. It is the exact definition of a cell reference.
• (C) Incorrect. A formula is different from a cell reference.
• (D) Incorrect. Cell colour is formatting information.
Step 4: Final conclusion.
\[
\boxed{\text{Cell Reference}=\text{Column Letter + Row Number}}
\]
Hence, the correct option is \(\boxed{(B)}\).