Which of the following statements is true?

a.) electrons are the smallest subatomic particle and have a negative charge, while protons and neutrons are approximately the same size as each other and have no charge.

b.) electrons are the largest subatomic particle and have a negative charge, while protons have a positive charge and neutrons have no charge.

c.) electrons are the smallest subatomic particle and have no charge, while protons and neutrons are approximately the same size as each other and have opposite charges.

d.) electrons are the smallest subatomic particle and have a negative charge, while protons have a positive charge and neutrons have no charge.