Coach Ankit is forming a team for the Annual Inter Galactic Relay Race. He has N students that train under him and he knows their strengths. The strength of a student is represented by a positive integer.

The coach has to form a team of K students. The strength of a team is defined by the strength of the weakest student in the team. Now he wants to know the sum of strengths of all the teams of size K that can be formed modulo 1000000007. Please help him.

Input
The first line contains the number of test cases T.
Each case begins with a line containing integers N and K. The next line contains N space-separated numbers which describe the strengths of the students.

Output
For test case output a single integer, the answer as described in the problem statement.

Constraints:
1 ≤ T ≤ 100
1 ≤ N ≤ 100000
1 ≤ K ≤ N
0 ≤ Strength of each student ≤ 2000000000
Strength of all the students are different.

SAMPLE INPUT
2
2 1
5 4
3 2
1 0 2

SAMPLE OUTPUT
9
1

Explanation

For first test case: 5+4=9, as team can only consist of 1 student.
For second test case: min(1,0) + min(1,2) + min(0,2) = 0+1+0 =1

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