Which type of boundary forms where two continental plates collide?
a. convergent boundary
b. divergent boundary
c. transform boundary
d. sliding boundary?

Because the rock making up continental plates is generally lighter and less dense than oceanic rock, it is too light to get pulled under the earth and turned into magma. Instead, a collision between two continental plates crunches and folds the rock at the boundary, lifting it up and leading to the formation of mountains and mountain ranges. 

At some convergent boundaries, an oceanic plate collides with a continental plate. Oceanic crust tends to be denser and thinner than continental crust, so the denser oceanic crust gets bent and pulled under, or subducted, beneath the lighter and thicker continental crust. This forms what is called a subduction zone.

A. - canada and the u.s 

The shia sect of islam is primarily different from sunni islam in the belief that the first legitimate imam following muhammad was imam ali. unlike the three caliphs that succeeded muhammad, ali was part of muhammad's clan (related to him). major shia caliphates include the fatimid and safavid caliphates.  the answer will be option c. shia read more on