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

Sentence: 'cooked fish and green broccoli share a single white plate'. Find frequency of the letter 'c'
3

Sentence: 'a man pushing a cart full of bananas'. Find frequency of the letter 'u'
2

Sentence: 'the bathroom is not clean and is ill attended'. Find frequency of the letter 'a'

4