Step 1: Recall each person's role:
General Cunningham was the first Director-General of the Archaeological Survey of India (founded 1861). Rakhal Das Banerjee discovered the Mohenjodaro site in 1922. John Marshall was Director-General of ASI in 1924 A.D., during whose tenure the Harappan sites were formally excavated. Dayaram Sahni discovered the Harappa site in 1921.
Step 2: Match each pair:
(a) Cunningham -> (ii) First Director of ASI; (b) Banerjee -> (iv) Discovered Mohenjodaro; (c) Marshall -> (iii) DG of ASI in 1924; (d) Sahni -> (i) Discovered Harappa.
Final Answer:
\[ \boxed{\text{a-(ii), b-(iv), c-(iii), d-(i)}} \]