(b)
(c)
or 
(d)
(e)
1(a)
(b)
(c) or
(d)
(e)
2(a) 
(b) R
(c) 
, Q
(d) 1 or T
3. Converse:
(a) Believing is sufficient for seeing.
(b) If it is less expensive, then I will buy it.
(c) If I can't finish the job, then I don't work hard.
(d) If you get an A in the final, then you get an A in Math 101.
Contrapositive:
(a) Not believing is sufficient for not seeing.
(b) If it is not less expensive, then I won't buy it.
(c) If I can finish the job, then I work hard.
(d) If you don't get an A in the final, then you don't get an A in Math 101.
4(a) S: Today is Sunday.
W: I do Web surfing.
Y: I do yard work.
N: the network is down.
R: It rains.
---------------
Y
(b)
one of the implications (simplification)
-----------------
R
-----------
Therefore the given conclusion is not correct.