Concept:
Cultural lag refers to the delay between changes in material culture and adjustments in non-material culture.
Step 1:
Technological and material changes often occur rapidly, while values, beliefs, and laws change slowly.
Step 2:
The theory of Cultural Lag was proposed by William F. Ogburn.
Step 3:
Ogburn explained that imbalance between material and non-material culture creates social problems and adjustment delays.
Step 4:
• Ruth Benedict worked in cultural anthropology.
• Talcott Parsons developed structural functionalism.
• W.G. Sumner is known for concepts like folkways and ethnocentrism.
Step 5:
Hence, the correct answer is William F. Ogburn.
\[
\boxed{\text{(3) William F. Ogburn}}
\]