The _____ schema design element declarations are not nested.

Consider the following statements: string str1 = "ABCDEFGHIJKLM";string str2; After the statement str2 = str1.substr(1,4); executes, the value of str2 is "____".

A. ABCD B. BCDE C. BCD D. CDE

C++ has a special name for the data types istream and ostream. They are called ____________________.

Fill in the blank(s) with the appropriate word(s).