If a pair of angles placed back to back in tension are connected by one leg of each angle, the neteffective area of the section, is

• A. a - [b/{1 + 0.35 (b/a)}]
• B. a + [b/{1 + 0.35 (b/a)}]
• C. a - [b/{1 + 0.2 (b/a)}]
• D. a + [b/{1 + 0.2 (b/a)}]