Use option a because it specifies the change that effected the marathon and how it effected it. option a also mentions how the change has effected the marathon in current times
he ballet of P. I. Tchaikovsky "The Silkcup," after the tale of Hoffmann; his opera "Eugene Onegin" (pictured scene from the opera), "The Queen of Spades" based on the works of A.S. Pushkin; Also the opera "Boris Godudunov" by M. P. Mussorgsky;
Free health care, more equalities and look into cases before going to death row