Which is an example of a formula in Excel

Which is an example of a formula in Excel
A: A1+A2
B: =A1+A2
C: SUM(A1\:A2)
D: None of these

In Excel every formula begins with an equal sign. For example =A1+A2 tells Excel to add the values of cell A1 and cell A2. Without the equal sign Excel would treat the entry as plain text. Functions like SUM(A1\