Explanation:

- Team A's Performance:

- In the first 30 overs, Team A scored 4.5 runs per over.

- Total runs for the first 30 overs = 30 x 4.5 = 135 runs.

- In the next 20 overs, the average was 5.5 runs per over.

- Total runs for the final 20 overs = 20 x 5.5 = 110 runs.

- Combined total for Team A = 135 + 110 = 245 runs.

- Team B's Performance:

- Team B scored 10 runs fewer than Team A, meaning they scored 245 - 10 = 235 runs.

- Finding Team B's Average:

- Total runs by Team B = 235 runs.

- Total overs played by Team B = 50 overs.

- Options and Calculation:

- To find the average runs per over: 235 runs ÷ 50 overs = 4.7 runs per over.

- Therefore, the correct option is Option 3, 4.7.

- The correct average runs per over scored by Team B is 4.7.