The correct answer is option 3: Eratosthenes.

Eratosthenes was a Greek philosopher who lived during the 3rd century B.C.E. He is credited with coining the term "Geography," which comes from the Greek words "geo" meaning earth and "graphein" meaning to write or describe.

Option 1: Euclid was a Greek mathematician who lived around the same time as Eratosthenes. Although he made significant contributions to mathematics with his work on geometry, he was not the philosopher who coined the term "Geography."

Option 2: Plato was a famous Greek philosopher, but he did not coin the term "Geography."

Option 4: Clio is one of the nine Muses in Greek mythology, the Muse of history. While she may have been associated with the recording of historical events, she did not coin the term "Geography."

In conclusion, Eratosthenes is the Greek philosopher who coined the term "Geography" in the 3rd century B.C.E.