Aman with type a blood marries a woman with type b. their offspring all have type ab blood. the pattern of inheritance is called a) codominance. b) sex-linkage. c) crossing over. d) incomplete dominance.

A  pattern of inheritance  is called codominance ( answer A)

  Explanation

Co  dominance is form  of dominance  whereby the alleles    of gene pair  is   heterozygote  and are fully  expressed.

This  results  in offspring with a  phenotype  that  is neither  dominant  nor  recessive.

A  person with  AB  has a  co  dominance  inheritance  since  both  A allele  and B allele  are  equally  expressed.

d i think its   answer d