Where a trustee is directed to sell trust-property or to invest trust-money in the purchase of property, he may exercise a reasonable discretion as to the time of effecting the sale or purchase.Illustrations (a) A bequeaths property to B, directing him to sell it with all convenient speed and pay the proceeds to C. This does not render an immediate sale imperative. (b) A bequeaths property to B, directing him to sell it at such time and in such manner as he shall think fit and invest the proceeds for the benefit of C. This does not authorise B, as between him and C, to postpone the sale to an indefinite period.