Which one of the following is the correct representation of set A = {2,4,8,16 .} in set builder form?

• A. {x: x = 2n where n N}
• B. {x: x = 2ⁿ where n N}
• C. {x: x = 4n where n N}
• D. {x: x = 2n+4 where n N}