**Concept:** **The question tests on the basics of Rounding/Approximation**

**Solution:**

3/11 is a recurring decimal and is = 0.272727... The 20th digit is 7 (As 7 is in the even place)

7/15 is also a recurring decimal and is = 0.46666... The 20th digit is 6.

The difference = 7 - 6 = 1**Option B**