Choose the right completion.1. Yesterday I quarreled with my boss about

Choose the right completion.
1. Yesterday I quarreled with my boss about ... I am terribly sorry.
a) who b) which c) that d) whom
2. I decided to quit politics ... I might have a great career in it.
a) because b) though c) since d) whenever
3. I am really anxious about this situation, ..., I hope we can find a solution.
a) ever since b) because of c) although d) however
4. ... various changes during the centuries, the cathedral remained largely unaltered.
a) Despite b) Despite of c) In spite d) Although