Answer: B
Correct answer: Cycles the selected cell reference between relative, absolute and mixed
While editing a formula, F4 cycles the reference at the cursor through its four forms: A1, $A$1, A$1, $A1, and back again. It saves typing dollar signs and is one of the most-used keys in Excel. Outside formula editing, F4 has a quite different role: it repeats the last action, which makes it useful for applying the same formatting to several places in turn. Its behaviour therefore depends entirely on the mode Excel is in. The other function keys are worth knowing alongside it. F2 edits the active cell in place. F9 recalculates all open workbooks - and, when part of a formula is selected in the formula bar, evaluates just that part, which is the standard way to debug a long formula. F11 creates a chart on a new sheet. F5 opens Go To, whose Special button selects all blanks, constants or formulas at once.