Option 1: Yellow - pink - blue

This option is incorrect. Scrubbing a turmeric stain on white clothes with soap will not cause the color to change from yellow to pink. Additionally, washing with water will not result in the color changing to blue.

Option 2: Yellow - reddish brown - yellow

This option is the correct sequence of color changes. Initially, the turmeric stain on white clothes is yellow. Scrubbing with soap may cause the color to change to reddish brown. However, when washed with water, the stain will return to its original yellow color.

Option 3: Yellow - reddish brown - blue

This option is incorrect. Scrubbing the turmeric stain with soap will not cause it to turn blue. Washing with water may not cause the color to change to blue either.

Option 4: Yellow - blue - pink

This option is incorrect. Scrubbing the turmeric stain with soap will not result in the color changing from yellow to blue. Additionally, washing with water will not cause the color to change from blue to pink.

Therefore, the correct answer is option 2: Yellow - reddish brown - yellow.