In which of the following is the prime factorization not complete?

• A.  \[70=2\times 5\times 7\]
• B.              \[28=2\times 2\times 7\]
• C.  \[48=2\times 2\times 2\times 2\times 3\]          
• D.  \[108=2\times 2\times 27\]