Step 1: Identify Subhadraharanam.
The incident of Arjuna eloping with Subhadra belongs to the Adiparva of the Mahabharata. Hence, C matches with Adiparva.
Step 2: Identify Shishupalavadham.
The killing of Shishupala at Yudhishthira’s Rajasuya sacrifice occurs in the Sabhaparva. Hence, A matches with Sabhaparva.
Step 3: Identify Sainyanirmanam.
The preparation for war, including military arrangements, belongs to the Udyogaparva. Hence, D matches with Udyogaparva.
Step 4: Identify Rajadharmanushashanam.
The discourse on duties of kingship belongs to the Shantiparva. Hence, B matches with Shantiparva.
Step 5: Conclusion.
Thus, the correct sequence of incidents according to parvas is C, A, D, B.