From the given options, choose the one that rightly explains the expression-

"To call a spade a spade"

Speak directly and frankly

The idiom "to call a spade a spade" most clearly explains speak directly and frankly. The idiom comes from the literal meaning of calling a spade a spade, which is to call something by its real name, even if it is not considered to be polite or politically correct. In the same way, when someone is said to be "calling a spade a spade," they are speaking directly and honestly, even if it means saying something that is not popular or easy to hear.

The other options are not as accurate. To speak rudely and disrespectfully means to speak in a way that is offensive or hurtful. To speak softly means to speak in a quiet voice. To speak diplomatically means to speak in a way that is tactful and considerate of others' feelings.