The complex(es) showing activity against cancerous cells is/are

           

 Concept:

• Platinum-based drugs are used in clinical research for cancer treatment. Cisplatin or cis-diamminedichloroplatinum(II) and its analogs are some of the most effective chemotherapeutic agents are in use for cancer treatment.
• The square planar Pt(II) is activated by slow hydrolysis of the anionic ligands. The corresponding cationic aqua complexes are thus formed by binding to DNA. 

Explanation:

• All of the complexes a, b, and c are thermodynamically and kinetically stable with respect to hydrolysis in blood where the concentration of Cl^- ion is very high. The two Cl atoms are cis to each other in both complex a and c.
• For complexes a and c, the bite distance between the two cis Cl ligands is appropriate to bind with DNA. So, The complex(es) showing activity against cancerous cells is/are (a) and (c).
• Complex b is an antitumoural and antimetastatic arene ruthenium complex. The complex [(C₆H₅Ph)Ru(N, N-en)Cl]⁺ is also used as an anticancer agent.

​Conclusion:

The complex(es) showing activity against cancerous cells is/are (a), (b), and (c).