Select the correct single-word replacement for the given statement.

A person who studies the relationship between handwriting and personality traits.

The correct option is Graphologist.

Explanation:
To find the correct single-word replacement for "A person who studies the relationship between handwriting and personality traits", let's analyze all the given options:

1. Graphologist: A specialist who analyzes handwriting to study and determine an individual's character, mind, or personality traits. The prefix "graph-" relates to writing or drawing, and the suffix "-logist" denotes a practitioner of a science or branch of study. Hence, this is the exact word required.
2. Etymologist: A scholar who studies the origin, history, and evolution of words and how their meanings change over time.
3. Oceanographer: A scientist who studies physical, chemical, and biological aspects of the ocean.
4. Philatelist: A person who collects, studies, or appreciates postage stamps and postal history.

Therefore, the term that correctly matches the given description is Graphologist.