Step 1: Understanding the question.
The question is asking for the interlimb angle of a vertical chevron fold, given the strike directions of the two limbs.
Step 2: Analyzing the strike directions.
The strike directions of the two limbs are given as S70°E and N55°E. To calculate the interlimb angle, we subtract the smaller angle from the larger angle.
The angle between the two limbs is:
\[
|70° + 55°| = 115°
\]
Step 3: Conclusion.
The correct answer is 115°, which is the interlimb angle of the fold.