__________ must be designed especially for this system to be effective; the principal difference is that the __________ vehicle that’s selected must give suitable rheological properties such as a fairly high viscosity.

__________ must be designed especially for this system to be effective

1.	__________ must be designed especially for this system to be effective; the principal difference is that the __________ vehicle that’s selected must give suitable rheological properties such as a fairly high viscosity.
A.	a)Ink
B.	b)Steel
C.	c)Aluminium
D.	d)Copper
Answer» B.