Rodrigo operated an illegal online sports betting syndicate from his condominium unit in Quezon City, collecting bets through an encrypted messaging application. Over the course of taxable year 2023, Rodrigo accumulated net receipts of ₱8,000,000 from the betting operations. He did not file any income tax return. When the Bureau of Internal Revenue (BIR) discovered his operations through a tip from a law enforcement agency, it assessed Rodrigo for deficiency income tax on his ₱8,000,000 in receipts. Rodrigo contested the assessment, arguing that: (a) illegal income is not "income" within the meaning of the NIRC because it is tainted by its criminal origin; and (b) even assuming it is taxable, requiring him to disclose such income in an income tax return would compel him to incriminate himself in violation of the 1987 Constitution. Are Rodrigo's arguments tenable? Explain your answer.