Credit spread call and put options

Dear all,

I have the following open questions:

  1. Are Credit options (based on price-binary) a zero sum game similar to Credit spread forwards?

  2. I am confused when to buy a credit spread put and call options

(My understanding is to buy credit spread call to cover the loss from the widening of credit spreads relative to Tbill and these are similar to put options)

  1. Can anyone guide me to an example as to why we would purchase credit spread put options.

  2. Why do we need to multiply with risk factor or with duration. What is the difference between both of them and which is more appropriate?

  3. In the below video I think they are referrring to call as put. The terminology isconfusing me.

Thanks much for your time.

http://www.youtube.com/watch?v=altg-wl0ZdQ