The correct option is A 2 less than 21 divided by 7.
Converting each of the given statements into mathematical expressions, we get:
(a) 2 less than 21 divided by 7
= (21 ÷ 7) - 2
(b) 21 divided by sum of 7 and 2
= 21 ÷ (7 + 2)
(c) Subtract 7 from 21 then divide the difference by 2
= (21 - 7) ÷ 2
(d) 21 minus 7 whole divided by 2
= (21 - 7) ÷ 2
Therefore, the matching statement for the given expression is:
"2 less than 21 divided by 7"