Please solve the programming task below using a self-contained code snippet in a markdown code block.

You are given a sorted integer array arr containing 1 and prime numbers, where all the integers of arr are unique. You are also given an integer k.
For every i and j where 0 <= i < j < arr.length, we consider the fraction arr[i] / arr[j].
Return the kth smallest fraction considered. Return your answer as an array of integers of size 2, where answer[0] == arr[i] and answer[1] == arr[j].
 
Please complete the following python code precisely:
```python
class Solution:
    def kthSmallestPrimeFraction(self, arr: List[int], k: int) -> List[int]:
```