Answer:
It is a Restrictive Indorsement
Explanation:
Restrictive Indorsement is when an instruction is given on a cheque that restricts its use.
In the case given above, Interstate Trucking is only to be paid if they deliver the lumber by May 1, 2010.
Use of the cheque outside this scenario is not possible.
A common example of this is 'For deposit only'. The customer will not be able to withdraw cash, but must deposit the cheque.