Errol, in His Home-Made Will, Leaves £80,000 to Kevin, to Be

Errol, in his home-made will, leaves £80,000 to Kevin, to be distributed under a discretionary trust to 'such of my old University friends who survive me, as Kevin in his absolute discretion shall decide.'
In relation to certainty of objects, which of the following statements is correct?

A) The trust is likely to be held certain, as there is a class of persons named, and it will be possible to show that at least one potential person will fall within the class.
B) The trust is likely to be held uncertain, as the words used to define the class are not defined with sufficient certainty.
C) The trust is likely to be held certain, as there is a clear class of potential objects from which Jonathan can select.
D) The trust is likely to be held uncertain, as it is not possible to know at the time the trust is created which friends will survive Errol.