Formulas within table cells always begin with
a. parentheses.
b. a symbol that looks like a backwards f.
c. an equals sign.
d. the autosum symbol.

The answer is C.

Formulas within table cells always begin with an equal sign.

Here is the sample of some of the formulas :

1. Sum (equation)
=SUM(5, 5) or =SUM(A1, B1) or =SUM(A1:B5)

2. Count ( to count number of cells or rows)
=COUNT(A1:A10)

3. Trim ( Get rid of any space in a cell)
=TRIM(A1)

4. Vlookup ( to look up data from a vertically structured table)
=VLOOKUP(lookup_value, table_array, col_index_num, range_lookup)

5. if statements
=IF(logical_statement, return this if logical statement is true, return this if logical statement is false)

Typically you use a cd.