Final answer:
The TRX row is the exercise most similar to the Horizontal Row - 1/2 Kneeling Inline Row, involving similar muscle groups and motions.
Step-by-step explanation:
The exercise that is similar to a Horizontal Row - 1/2 Kneeling Inline Row is A) TRX row. This is because both exercises target similar muscle groups and involve a pulling motion that works the back, shoulders, and biceps. The TRX row, like the Horizontal Row, requires core stability and can be adjusted in difficulty by changing the body's angle relative to the ground. On the other hand, a Standing inline press focuses on pushing rather than pulling, Chin-up is more vertically oriented, and the X-pulldown typically uses a cable machine and has a different movement pattern compared to a horizontal row.