In 1905, Alfred Binet and Theodore Simon, made the first successful attempt to formally measure intelligence. In 1912 ______ designed the concept of Intelligence Quotient (IQ).

William Stern

The correct answer is Option (3) → William Stern

In 1912, William Stern, a German psychologist, devised the concept of Intelligence Quotient (IQ). IQ refers to mental age divided by chronological age, and multiplied by 100.