how to run my unsafe code in c#

hello guys .. how r u ? hope u r all fine ...

i have a question for yor that ... i m facing this error "Unsafe code may only appear if compiling with /unsafe" in my project 
on which i m working on asp.net 3.5 using C#  and i m unable to find solution about this error .... so please help me and guide me that how can i solve this error 

Thanks ...