"Coffee Canephora has two copies of each chromosome but Coffee Arabica contains multiple copies. This makes it much more difficult for Coffee Arabica to interbreed with other species." -> Arabica has multiple chromosome copies
-> Option 1: Arabica - Has "more than two copies of each chromosome" ✓
-> Option 2: Robusta (Canephora) - Has "two copies of each chromosome"
-> Option 3: Eugenioides - No chromosome information given
-> Option 4: Blend - Not a species, but a mixture
The answer is Option 1 - Arabica.
Note: Look for the term "polyploidy" - it means multiple chromosome copies!