For the author, silence is necessary in order to surmount

The correct option is tendency to overstate.

Step-by-Step Explanation:
1. Understanding the Core Concept: To "overstate" means to exaggerate, embellish, or express something too strongly. It is a common linguistic tendency where an author or speaker might use hyperbole or excessive language rather than sticking strictly to the precise truth.
2. The Role of Silence: In writing and communication, silence represents a deliberate pause, reflection, and self-restraint. By practicing silence, the author allows themselves the necessary time to filter out impulsive, exaggerated claims. It acts as a cooling-off period that prevents the natural inclination to amplify or over-dramatize a point.
3. Surmounting the Tendency: Therefore, silence is necessary for the author to surmount (or overcome) their tendency to overstate. It ensures their language remains measured, precise, and authentic.
4. Why Other Options are Incorrect:
- Constitutional shyness and hesitancy in speech are inherent personal traits or anxiety-related behaviors; silence would typically reinforce or stem from these conditions rather than being a chosen tool to overcome them.
- Suppression of thoughts refers to hiding or burying ideas, whereas the purposeful use of silence is meant to refine expression rather than suppress the underlying thoughts entirely.