In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'group of cars on the road with the sun setting behind it'. Find frequency of the letter 'd'
2

Sentence: 'a half eaten doughnut in a persons hand'. Find frequency of the letter 'h'
3

Sentence: 'a group of people walking down a street next to buildings'. Find frequency of the letter 'o'

5