Which genotype represents a true dihybrid condition?

When a cross is made between $Ttrr$ and $Rrtt$, the phenotypic ratio of their progeny will be:

When a cross is made between a tall plant with yellow seeds $(TtYy)$ and a tall plant with green seeds $(Ttyy)$,what proportions of phenotypes in the offspring could be expected to be:
$(a)$ Tall and green.
$(b)$ Dwarf and green.

In a plant,red fruit $(R)$ is dominant over yellow fruit $(r)$ and tallness $(T)$ is dominant over shortness $(t)$. If a plant with $RRTt$ genotype is crossed with a plant that is $rrtt$,what will be the phenotypic ratio of the offspring?

In humans,a male produces sperm with genotypes $AB, Ab, aB,$ and $ab$. What would be the genotype of this individual?

How many types of gametes may be produced by genotype $D/d : E/e : F/f$?