Goh offers to sell his IBM computer to Hassan and stated that acceptance in writing must reach his (Goh's) office by 15 January 1993. Explain the legal situation in the following circumstances:-

a)Hassan posted a letter of acceptance to Goh on 10 January 1993 which arrives at Goh's office on 16 January 1993.

b)Hassan telephones Goh on 14 January 1993 accepting the offer but Goh insisted that Hassan must accept in writing.

c)Hassan fax a letter to Goh using his fax machine at 4 p.m. on 15 January 1993 but Goh's fax machine was out of order at the time. By the time Hassan rushed to Goh's office, the office was already closed.