Ballpoint pen: Identify the inventor associated with the successful modern version. Full question: Who invented the ballpoint pen (commercially successful design)? Choose the correct option.

Given data

• Topic: Writing instruments and their inventors.

Concept / Approach
László Bíró patented and popularized the modern, commercially successful ballpoint pen in the 20th century, using quick-drying ink and a rolling ball mechanism.

Option analysis
Bíró: Correct. Waterman: Fountain pen innovations. Bell: Telephone. Lamarr: Spread-spectrum co-inventor (communications), not pens.

Final Answer
László Bíró.