Found in the northern Indian Ocean, five species of sea turtles each have threats from accidental catches by fishermen targeting other species, and the direct harvest of turtles or their eggs for food or turtle shell material for commercial use.
A. Found in the northern Indian Ocean, five species of sea turtles each have threats
B. Five species of sea turtles each, which are found in the northern Indian Ocean, has threats
C. Found in the northern Indian Ocean, each of the five species of sea turtles have threats
D. Each of the five species of sea turtles, which is found in the northern Indian Ocean, has threats
E. Each of the five species of sea turtles, which are found in the northern Indian Ocean, have threats
In A, the modifier "Found...Ocean" is technically modifying "five". So I think that is not correct. However, in D the use of 'is' in modifying phrase is not correct where 'which' refers to 'turtles' and in E, 'have threats' actually is wrong w.r.t the subject 'each of ....'
I am sure B and C are not correct.
Not sure which one to pick!!!