Which of the following is an example of shape in Piet Mondrian's Composition with Red, Yellow, and Blue?

In Piet Mondrian's "Composition with Red, Yellow, and Blue," the most prominent example of shape is the use of rectangular blocks of color. Mondrian's work is characterized by a grid-like structure composed of vertical and horizontal lines, creating various rectangles and squares filled with primary colors—red, yellow, and blue—along with the use of white and black. This systematic arrangement demonstrates his exploration of abstract form and purity of color, employing geometric shapes to convey harmony and balance within the composition. His reliance on simple shapes, devoid of overt symbolism, reflects the essence of Neoplasticism, a movement he pioneered, emphasizing aesthetic simplicity and structural clarity.