Select the correct answer. What is the standard lettering height of lowercase letters when used in combination with uppercase letters? A. Lowercase letters must be about one-fourth the height of uppercase letters. B. Lowercase letters must be about twice the width of uppercase letters. C. The lower part of the lowercase letter must be about two-thirds the height of the capital letter. D. The upper part of the lowercase letter must be about two-thirds the height of the capital letter.