Which of the following sets of elements are arranged in order of decreasing atomic size in the Periodic Table?

• A ₆C, ₄Be, ₇N,₈ O
• B ₄Be,₆ C,₇ N,₈ O
• C ₈O, ₇ N, ₆C, ₄Be
• D ₇N, ₈O, ₆C,₄BeBe