Answer:
89/56 (first option)
Explanation:
The LCD (or Least Common Denominator) of all the fractions is 840.
5/7 (the smallest number) is equivalent to 600/840, while 7/8 (the largest number) is equivalent to 735/840.
600/840 + 735/840 = 1335/840, which reduces to 89/56.
Hope this helps!