If the new airboat does what it is to be doing—travel at high speeds undeterred by sandbars, crocodile-infested mudflats, or marshy hippo haunts—it could revolutionize transport on the 2,900-mile-long Congo River.
(A) If the new airboat does what it is to be doing
(B) If the new airboat does what it is supposed to do(C) If it does as the new airboat is supposed to do
(D) Doing what it is the new airboat is supposed to do
(E) Doing what the new airboat is to be doing
Answer is B
Explanation :
If the new airboat does what it is to be doing—travel at high speeds undeterred by sandbars, crocodile-infested mudflats, or marshy hippo haunts—it could revolutionize transport on the 2,900-mile-long Congo River.
(A) If the new airboat does what it is to be doing --- to be doing is not correct
(B) If the new airboat does what it is supposed to do - correct- proper conveying meaning
(C) If it does as the new airboat is supposed to do It is not good way to use . and What is subject to it is representing
(D) Doing what it is the new airboat is supposed to do --It is not good way to use . and What is subject to it is representing
(E) Doing what the new airboat is to be doing --It is not good way to use . and What is subject to it is representing