Cross between $F_1$ plant and recessive female plant is called

What is the cross between the progeny of $\mathrm{F}_{1}$ and the homozygous recessive parent called? How is it useful?

Which one of the following can be explained on the basis of Mendel's Law of Dominance?

$A$. Out of one pair of factors one is dominant and the other is recessive.

$B$. Alleles do not show any expression and both the characters appear as such in $F_2$ generation.

$C$. Factors occur in pairs in normal diploid plants.

$D$. The discrete unit controlling a particular character is called factor.

$E$. The expression of only one of the parental characters is found in a monohybrid cross.

Choose the correct answer from the options given below:

Definitions / Explanation : Punnett square
 

For the expression of traits genes provide only the potentiality and the environment provides the opportunity. Comment on the veracity of the statement.