While punctuating a sentence it is important to capitalize the first letter of the sentence. Also, it is important to capitalize the proper nouns such as the name of a person, place or organization. In the given sentence, ‘Chandigarh’ is the name of a city while ‘India’ is the name of a country. Therefore the first letter of the names should be in uppercase. Hence options B and C are incorrect. Further, a comma is used to indicate the division between ideas and is commonly used to differentiate the introductory phrases from the subject of the sentence. In the given sentence "According to a survey” is the introductory phrase; hence a comma needs to be used after it to separate it from the subject of the sentence. Therefore option D is correct, while option A is incorrect.