Step 1: Read each pair as a category and one example from that category.
Fruit paired with tomato, Pen paired with Natraj, Non-veg paired with tofu, Bike paired with splendor - each pair should show a genuine member of its category.
Step 2: Test each pair for genuineness.
Tomato is commonly treated as a fruit in botany, Natraj is a real pen brand, and Splendor is a real bike model - these three hold up fine.
Step 3: Check the odd pair.
Tofu is a soy based plant product, not a non-veg item at all, so this pairing does not fit the pattern the other three follow.
\[ \boxed{\text{Non-veg - tofu}} \]