Weighing more than 300 pounds and standing over 2 meters tall, the flightless bird Titanis walleri, which lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey, is the most fearsome representative of the aptly named “terror birds.” (A) Weighing more than 300 pounds and standing over 2 meters tall, the flightless bird Titanis walleri, which lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey, is the most fearsome representative of the aptly named “terror birds.” - Correct
(B) The most fearsome representative of the aptly named “terror birds,” the flightless bird Titanis walleri, which lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey, weighing more than 300 pounds and standing over 2 meters tall. - Not even a complete sentence - no verb
(C) The most fearsome representative of the aptly named “terror birds,” the flightless bird Titanis walleri weighed more than 300 pounds, stood over 2 meters tall, having lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey. - parallelism issue
The flightless bird Titanis walleri
-weighed more than 300 pounds
-stood over 2 meters tall
-
having lived in Florida about 2 million years ago
-may have evolved opposable thumbs to subdue struggling prey
"Having" doesn't match the grammatical structure of the other list items, so our list doesn't have correct parallelism
(D) Weighing more than 300 pounds and standing over 2 meters tall, the flightless bird Titanis walleri lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey, the most fearsome representative of the aptly named “terror birds.” - modifier issue at the end- this sentence describes the Titanis walleri's prey as the most fearsome "terror bird". This doesn't make sense - we want to describe the Titanis walleri as the most fearsome "terror bird", not the things it eats
(E) The flightless bird Titanis walleri, which weighed more than 300 pounds and stood over 2 meters tall, lived in Florida about 2 million years ago and may have evolved opposable thumbs to subdue struggling prey, the most fearsome representative of the aptly named “terror birds.” - same as D
Answer A