Step 1: Concept
Terpenes are classified based on the number of isoprene ($C_{5}H_{8}$) units in their structure.
Step 2: Meaning
A sesquiterpene contains 15 carbon atoms ($C_{15}$), formed from three isoprene units.
Step 3: Analysis
Santalol is the primary alcohol constituent responsible for the fragrance of sandalwood oil. It has a $C_{15}$ structure, which classifies it as a sesquiterpene.
Step 4: Conclusion
Therefore, Santalol is a sesquiterpene alcohol.
Final Answer: (B)