What is the result when a plant with red flowers (RR) is crossed with a plant with yellow flowers (YY), assuming the alleles are codominant?

flowers with all red petals
flowers with all yellow petals
flowers with all orange petals
flowers with a mixture of red and yellow petals

Assuming that the alleles for flower color are codominant, the result of crossing a plant with red flowers (RR) with a plant with yellow flowers (YY) would produce flowers with a mixture of red and yellow petals.