S, who lives in Upington, sends P, who lives in Cape Town, a letter by post in which she offers to sell him her (S's) motorcycle, a collector's piece, for R100 000. She states in her letter that her offer will expire on 1 February. P accepts S's offer by letter which he posts on 8 January. The postal service is disrupted by a strike which starts on 6 January and only ends on 1 February. During this period no post is delivered. S receives the letter only on 7 February and only reads it on the next day. Did a valid contract of sale arise between S and P and, if so, where and when was the contract concluded? Advise P fully. Substantiate your advice and refer to relevant case law. Do not discuss option contracts.