Well-defined or Not?

All the colors in the rainbow.

• Well-defined

• not well-defined

All the points that lie on a straight line.

• Well-defined

• not well-defined

All the honest members of the family.

• Well-defined

• not well-defined

All the consonants of the English alphabet.

• Well-defined

• not well-defined

All the tall boys of the school.

• Well-defined

• not well-defined

All the hardworking teachers in a school

• Well-defined

• not well-defined

All the prime numbers less than 100.

• Well-defined

• not well-defined

All the letters in the word geometry.

• Well-defined

• not well-defined

set of honest people in a class.

• Well-defined

• not well-defined

set of senior citizens

• Well-defined

• not well-defined