The appropriate choice is z = 1.41.
The empirical rule tells you 68% of the distribution is within 1 standard deviation, so p(z > 1) ≈ 0.17. This means the z value is more than 1 for the probability to drop to 0.08. The only choice that is greater than 1 is 1.41. (The number is actually about 1.40507.)
