Explanation:

- Total coins in bags: A = 580, B = 510, overall = 1510. Hence, C = 1510 - 580 - 510 = 420.

- The copper coin ratio in A, B, and the gold coins in C is 3:2:4. Let the copper coins in A be 3x. Then, in B, it's 2x, and gold in C is 4x.

- Silver coins in B are 60 more than copper in B: 2x + 60.

- Gold coins in B are 25% less than silver in A. Let silver coins in A be y, then gold in B is 0.75y.

- Total gold coins in A, B, and C = 570.

- Total copper to silver ratio is 20:27.

Using the information:

1. Copper Coins: $3x+2x+\text{Copper in C}=\text{Total copper coins}$

2. Silver Coins: $y+(2x+60)+\text{Silver in C}=\text{Total silver coins}$

3. Use equations to find x and then calculate the silver coins in B and C.

Following calculations can get the value of x, y, and respective silver coins easily. The value for the coins should satisfy all conditions of ratio and totals.

Total number of silver coins in B and C together will be 280.

- Correct Answer: Option 4, 280