The correct option is
A Hurrah
! My favourite team has won.
Option A - 'Hurrah' is an exclamatory word and we must use an exclamation mark here and not a comma. 'My favourite team has won' is a simple sentence and thus we can't use a question mark here. Hence, option A is incorrect.
Option B - 'Hurrah' is an exclamatory word and we must use an exclamation mark here and not a comma. 'My' should begin with a capital 'M' as it is a new sentence. Hence, option B is incorrect.
Option D - 'Hurrah' is an exclamatory word and we must use an exclamation mark here and not a comma. The remaining sentence is a simple sentence and not an exclamatory sentence and thus we can't end the sentence with an exclamation mark. Hence, option D is incorrect.
Option C - As 'hurrah' is an exclamatory word, the exclamation mark is used. As the sentence is a simple sentence, it ends with a full stop. Hence, option C is the correct answer.
'Hurrah! My favourite team has won.'