$2.$ Which of the following is not one of the research$-$based criticisms directed towards Maslow's hierarchy of needs?

b$.$ c$.$

There is no validation for the hierarchy of the needs including the two$-$level deficiency needs and growth needs

Validity of the hierarchy is dubious

If self$-$actualization is a universal need, why is the percentage of self$-$actualizers so low?

d$.$ There is no relationship between need importance $($in the hierarchy of the needs$)$ and age