Which of these paintings is not an example of the use of science-based principles in art
a. leonardo da vinci's the last supper
b. leonardo da vinci's mona lisa
c. georges seurat's a sunday on la grande jatte

The odd one out is Mona Lisa. It is a romantic and spiritual evocation of a person and a character. It is called also La Gioconda after Lisa del Giocondo (1479 – 1542 or 1551.) She was also known as Lisa Gherardini [her unmarried name] and was a member of the Gherardini family of Florence and Tuscany. The portrait was commissioned by her husband and painted by Leonardo da Vinci. It is clearly and overtly a picture of a loving woman, for her loving husband. Also, clearly it is a "modern" painting in the sense that it showed the influences of the Renaissance rather than being Mediaeval in style. But Da Vinci seemed to be experimenting with his style and method. In later works, he was more scientific and "modern" in his layout and visual "tricks."

The image isn’t here.