Step 1: Understanding the Question:
Malaysia's economy has historically been closely tied to plantation agriculture introduced during the colonial period.
Step 2: Key Fact:
Rubber (natural rubber, Hevea brasiliensis) has been Malaysia's signature plantation crop since the early 20th century, and Malaysia remains among the world's leading natural-rubber and palm-oil producers.
Step 3: Eliminating other options:
Coffee and tea are minor crops there; sugarcane is not a major Malaysian plantation crop (it is more associated with countries like Cuba, Brazil, India).
Step 4: Final Answer:
\[ \boxed{\text{Rubber}} \]