Which of the following is a correct statement?

To determine the correct statement regarding biological nomenclature, let us review the universal rules of binomial nomenclature established by Carl Linnaeus:

1. Origin and Language: Biological names are generally in Latin and written in italics (or underlined when handwritten) to indicate their Latin origin, not bold. Therefore, the option stating they are printed in bold to indicate Latin origin is incorrect.
2. Language: Biological names are generally in Latin, not Greek. Thus, the option stating they are generally in Greek is incorrect.
3. Structure of the Name: In a biological name, the first word represents the genus (generic name), while the second word denotes the specific epithet. The option stating the first word represents the specific epithet and the second denotes the genus is incorrect.
4. Capitalization: The genus name always starts with a capital letter, while the specific epithet starts with a small letter (e.g., Mangifera indica). Therefore, the statement "the first word denoting the genus starts with a capital letter by the specific epithet starts with a small letter" (where "by" is a typo in the option representing "while") is the correct statement.

Hence, the correct option is: the first word denoting the genus starts with a capital letter by the specific epithet starts with a small letter.