Step 1: Analyze the statements.
- Statement (I) claims that diglossia and dialect continuum are synonymous. However, these two concepts are not synonymous. Diglossia refers to a situation where two distinct varieties of a language are used in different social contexts, while a dialect continuum refers to a range of dialects spoken in a geographical area where neighboring dialects are mutually intelligible, but the dialects at the extremes are not. Thus, statement (I) is incorrect.
- Statement (II) claims that bilingual speakers are also bidialectal. While bilingual speakers speak two languages, bidialectal speakers use two dialects of the same language. These are distinct concepts. Therefore, statement (II) is also incorrect.
Step 2: Conclusion.
Both statement (I) and statement (II) are incorrect, which makes option (B) the correct answer.