Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Hand | 1 credit | 2 credits | 3 credits | 4 credits | 5 credits |
| --- | --- | --- | --- | --- | --- |
| Royal flush | 250 | 500 | 750 | 1000 | 4000* |
| Straight flush | 60 | 120 | 180 | 240 | 400 |
| Four aces | 400 | 800 | 1200 | 1600 | 2000 |
| Four of a kind, 2-4 | 100 | 200 | 300 | 400 | 500 |
| Four of a kind, 5-K | 50 | 100 | 150 | 200 | 250 |
| Full house | 8 | 16 | 24 | 32 | 40 |
| Flush | 5 | 10 | 15 | 20 | 25 |
| Straight | 4 | 8 | 12 | 16 | 20 |
| Three of a kind | 3 | 6 | 9 | 12 | 15 |
| Two pair | 1 | 2 | 3 | 4 | 5 |
| Jacks or better | 1 | 2 | 3 | 4 | 5 |
| Theoretical return | 98.68% | 98.68% | 98.68% | 98.68% | 99.92%* |
Question:
what's the best type of four of a kind to win?
Answer:
Four of a kind, 2-4