Imagine that at the start of their negotiations, Pretty gave Clive a choice of three horses that he owned and said that when Clive arrives in Cape Town he must come and choose which of the horses he wants. In the meantime, Clive must transfer the R500 000 to Pretty before coming to choose a horse. With reference to what constitutes certainty of performance as a requirement for a valid contract, explain whether Pretty's performance will be considered to be certain in this scenario