助詞N5
〜か（並列）
or (alternative)
Structure
N1 + か + N2 / 文 + か + 文 + か
Explanation
Connects two nouns or clauses for alternatives. N1+か+N2 = N1 or N2. Clause+か+clause+か = whether ~ or ~.
Examples
コーヒーかお茶を飲みます。
I will drink coffee or tea.
行くか行かないか、まだ決めていません。
I haven't decided whether to go or not.
Note
か in a clause is a listing particle (choice); at sentence end it is a question particle. Mid-sentence か falls, sentence-end か rises.