Watermelons are sometimes adulterated with Erythrosine, a synthetic red dye. This dye is harmful and used illicitly to make the fruit appear more vibrant and appealing. The use of Erythrosine in food products is not recommended as it poses potential health risks.
- Carmoisine is another synthetic dye, but it is not typically used to adulterate watermelon.
- Rhodamine B is used as a dye in some applications, but it is not the typical adulterant found in watermelon.
- Auramine is also a dye but is not commonly used to adulterate watermelon fruits.
Thus, the correct answer is option (2): Erythrosine.