The question provides the distribution of 100,000 tourists who visited India in a certain year, and asks for the number of Japanese tourists below the age of 39. Without any charts or graphs provided, it`s challenging to explain each option accurately. However, given that the correct answer is 4, we can assume that 4,000 Japanese tourists below the age of 39 visited India that year.

Each option likely refers to a different calculation one could draw from given data.

Option 1 (10,000) could perhaps be all the Japanese tourists that visited.

Option 2 (8,000) might represent Japanese tourists above a certain age or those who visited a particular part of India.

Option 3 (6,000) could bear significance to another group within the Japanese tourists or another age group.

Option 4 (4,000) is the correct number of Japanese tourists below the age of 39 based on the information provided.

Further explanation would require the breakdown of the data from the provided charts which is missing in the question.