On Monday, there were thrice as many peanuts in Sack X as Sack Y. On Tuesday, 3952 peanuts in Sack X were sold. Now there were thrice as many peanuts in Sack Y as Sack X. How many peanuts were there in Sack X at first?
(a) 4644
(b) 6644
(c) 4446
(d) 4466