Use the following description and figure to answer the questions below. In a particular plant,leaf colour is controlled by gene locus D.Plants with at least one allele D have dark green leaves,and plants with the homozygous recessive dd genotype have light green leaves.A true-breeding dark-leaved plant is crossed with a light-leaved one,and the F₁ offspring is allowed to self-pollinate.The predicted outcome of the F₂ is diagrammed in the Punnett square shown below,where 1,2,3,and 4 represent the genotypes corresponding to each box within the square. -Which of the boxes correspond to plants with a heterozygous genotype?
A)1 B)1 and 2 C)1, 2, and 3 D)2 and 3 E)2, 3, and 4