Explanation:

• Correct. The Montagu-Chelmsford Reforms were introduced during Lord Chelmsford's tenure, bringing about significant changes in the administrative system, including the introduction of diarchy in provinces.

• Correct. The Rowlatt Act, which was highly unpopular and led to widespread protests, was enacted during Lord Chelmsford's time as Viceroy.

• Correct. The All India Khilafat Committee was formed during his tenure, which aimed to protest against the injustices done to the Ottoman Caliphate after World War I.

• Incorrect. The Simon Commission was constituted later, in 1927, after Lord Chelmsford's tenure as Viceroy had ended.