It is said:
"We will return an array of subarrays or of tuples (in C an array of Pair) or a string.".
Did you read that ?
Furtherrmore you have the following "Sample Tests":
[Test]
public void Test01() {
Assert.AreEqual("[[1, 1], [42, 2500], [246, 84100]]", SumSquaredDivisors.listSquared(1, 250));
}
[Test]
public void Test02() {
Assert.AreEqual("[[42, 2500], [246, 84100]]", SumSquaredDivisors.listSquared(42, 250));
}
[Test]
public void Test03() {
Assert.AreEqual("[[287, 84100]]", SumSquaredDivisors.listSquared(250, 500));
}
}