If we convet it to other from can be written as :
f(A, B, C, D) = $\sum (2, 6, 8, 10)$
Which can be written as:
$A{}'B{}'CD{}' + A{}'BCD{}' + AB{}'C{}'D{}' + AB{}'CD{}'$
which can be reduced to
$A{}'CD{}' + AB{}'C{}'D{}' + AB{}'CD{}'$
Hence the answer is C.