Answer:
The answer is indeed letter b. to tell a white lie.
Explanation:
Idioms are groups of words that form an expression whose meaning cannot be related directly to the meaning of each word. That is, if we were to interpret each word in its literal sense, the meaning of the expression would be incorrect.
The idiom "to tell a white lie" uses the word "white" even though a lie does not have a color. The true meaning refers to the fact that this kind of lie - a white lie - does not do any harm to anyone.
