Explanation:

Let's evaluate the expression using the given meanings for each symbol:

- ‘A’ means ‘+’.

- ‘B’ means ‘-’.

- ‘C’ means ‘×’.

- ‘D’ means ‘÷’.

Now, apply these to the expression: 20 B 30 A 15 C 20 D 5.

- Start with: 20 B 30, which means 20 - 30 = -10.

- Then: -10 A 15, which means -10 + 15 = 5.

- Next: 5 C 20, which means 5 × 20 = 100.

- Finally: 100 D 5, which means 100 ÷ 5 = 20.

- Correct Option is: Option 4, 40.