Part of peer editing a classmate's essay is reviewing it for proper overall MLA document formatting. Which follows proper MLA formatting?

a) Text should be double-spaced, the header left-aligned, and the title centered.
b) Text should be single-spaced, the header left-aligned, and the title centered.
c) Text should be single-spaced, and the header and title left-aligned.
d) Text should be double-spaced, and the header and title centered.