We can use the first three lines to conclude ~L

1. (S & (S>W)) & (W>~L)

2. W & (W>~L)

3. Therefore ~L

Similarly, we can use the next two lines to conclude ~I

1. D & (D>~I)

2. Therefore ~I

We can now use the above to conclude C

1. (~L & ~I) is equivalent to ~(L v I)

2. ~(L v I) & ((L v I) v C)

3. Therefore C

Now we can conclude using the following:

1. C & (C>B)

2. Therefore B