Yes I agree with 18. You added 6 + 1 for the top part. That’s 7 and you continued on with the formula. You did base plus base or 7 + 5 which is 12. Then you divided by 2. 12 divided by 2 is 6. Then you multiplied the height (3m) by 6. 3 x 6 is 18. (B) would be right.
