Write a true biconditional, and show that both implied conditionals are true. Choose the correct answer below.

A. A true biconditional is "A whole number is even if and only if it is divisible by 2.' " One of the implied conditionals is "If a whole number is even, then it is divisible by 2.'' The other is "If a whole number is divisible by 2, then it is even." Both of these conditionals are true by the definition of an even number.
B. A true biconditional is "A whole number is divisible by 3 if and only if it is divisible by 6." One of the implied conditionals is "If a whole number is divisible by 3, then it is divisible by 6." The other is "If a whole number is divisible by 6, then it is divisible by 3." Both of these conditionals are true because of the properties of divisibility and the fact that 6 is a multiple of 3.
C. A true biconditional is^=x^2 if and only if x>0." One of the implied conditionals is ''ifx^2 , then x>0 " The other is "If x>0 , then x^2 " Both of these conditionals are true because the graph of y=x^2 is below the graph of y=x^3 for all positive real numbers x and not for any other values of x.
D. A true biconditional is ''sqrt(x)≥slant x if and only if 0 ." One of the implied conditionals is "If sqrt(x)≥slant x , then 0 ." The other is ''If0≤ x≤ 1 , then sqrt(x)>x.'' Both of not a real number, the case of x<0 does not need to be considered. y=sqrt(x) is above the graph of y=x for 0≤ x≤ 1. Because the square root of a negative number is these conditionals are true because the graph of and not for x>1