Which of the following pseudo code snippets correctly calculates the sum of numbers from 1 to n using recursion?

Sure! Here are the pseudo code snippets that calculate the sum of numbers from 1 to n using recursion:

Snippet 1:

function calculateSum(n):
    if n == 1:
        return 1
    else:
        return n + calculateSum(n-1)

Snippet 2:

function calculateSum(n):
    if n == 0:
        return 0
    else:
        return n + calculateSum(n-1)

Snippet 3:

function calculateSum(n):
    if n <= 0:
        return 0
    else:
        return n + calculateSum(n-1)

Out of these three snippets, Snippet 1 and Snippet 2 correctly calculate the sum of numbers from 1 to n using recursion. Snippet 3 is incorrect because it includes the case where n is less than or equal to 0, which would result in an infinite recursion.