From this verse we can understand that Brahma is the name of the post and that the person occupying the post has a particular name also. From Bhagavad-gita: imam vivasvate yogam. Vivasvan is the name of the present predominating deity of the sun. He is generally called Surya, the sun-god, but he also has his own particular name. The governor of the state is generally called raja-pala, but he also has his own individual name. Since there are hundreds and thousands of Brahmas with different names, Krsna wanted to know which of them had come to see Him.