Vector Growth and Iterator Invalidation

Consider the following C++ code:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> v = {1, 2, 3};
    v.reserve(100);
    auto it = v.begin();
    v.push_back(4);       // (1)
    std::cout << *it;     // (2)
}

Which statement is true?