Mosquitoes are known to be vectors for various diseases, meaning they can transmit the pathogens that cause these diseases from one individual to another. In this question, we are asked to identify the disease that mosquitoes cannot transmit. Let`s analyze each option to determine the correct answer.

Option 1: Yellow fever

Mosquitoes, specifically certain species of Aedes mosquitoes, are indeed vectors for transmitting the virus that causes yellow fever. Therefore, option 1 is incorrect.

Option 2: Dengue fever

Again, certain species of Aedes mosquitoes are responsible for transmitting the dengue virus, making mosquitoes a vector for this disease. Thus, option 2 is also incorrect.

Option 3: Filaria

Here, the provided answer is incorrect. Mosquitoes, particularly the Anopheles and Culex species, can transmit filarial parasites to humans, causing filariasis. Therefore, option 3 is incorrect, and the correct answer should be stated as option 4.

Option 4: Kala-azar

Kala-azar, also known as visceral leishmaniasis, is primarily transmitted to humans through the bite of infected female sandflies. Mosquitoes are not vectors for kala-azar, making option 4 the