Final answer:
The Phoenicians relied on stars and constellations as their main navigational tools during their trading voyages across the Mediterranean Sea. The correct option is A.
Step-by-step explanation:
The important tools that the Phoenicians used for finding their way on their trading voyages were stars and constellations. This method of navigation involved identifying and following patterns in the night sky to determine the direction and position at sea.
They did not have access to compasses or sophisticated maps and charts like we have today nor did they use astrolabes during the peak of their maritime activities. The knowledge of the stars was crucial for navigation across the vast Mediterranean Sea and for setting up trade networks reaching far and wide, including the establishment of numerous colonies along the coastal regions.