The correct answer is Option B:

Solution:
Considering the given options.

Option A.   

Option B.

On Option B:  Considering the given number pattern.

Here, the numbers are decreasing.
So, we first find the rule.

Note that:
50 - 10 = 40
40 - 10 = 30
30 - 10 = 20
20 - 10 = 10

So, the rule is "subtract 10", and this is the required answer.

Hence, the correct counting pattern with the rule ‘subtract ten’ is Option B: