Scientists pin-pointed the location of colour-processing perception centres in human visual cortex by a method named

Correct option (b) PET scanning

Explanation :

PET (Positron Emission Tomography or Positron Emission Tomographic Scanning) is a diagnostic technique based on detection of positrons (positively, charged electrons) emitted by radio isotopes such as ¹¹C, ¹³N, ¹⁵O and ¹⁸F generated by the cyclotron. These radio isotopes are then incorporated by chemical methods into biological molecules such as glucose, amino acids, carbon dioxide and ammonia and then injected in very small amounts into or inhaled by the experimental animals or human subjects. These positron emitting compounds are injected into the blood-stream and are taken up in greater concentration by areas of tissues that are more metabolically active. Specific centres in brain, like colour processing in visual cortex of humans can be detected by PET.