A.\(4.\)                           
B.\(4i.\)                 
C.\( - 1.\)                        
D.\( - i.\)

A.\(2.\)                   
B.\(\sqrt {2.} \)           
C.\(\sqrt {10} .\)    
D.\(10.\)

A.\(3x + y - z - 7 = 0.\)  
B.\(x + 4y - 2z + 6 = 0\).   
C.\(x + 4y - 2z - 6 = 0\).  
D.\(3x + y - z + 7 = 0.\)

A.\(\left\{ \begin{array}{l}x = 1 + 2t\\y = 2t\\z = 1 + t\end{array} \right..\)   
B.\(\left\{ \begin{array}{l}x = 1 + t\\y = t\\z = 1 + t\end{array} \right..\)   
C.\(\left\{ \begin{array}{l}x = 1 - t\\y = t\\z = 1 + t\end{array} \right..\)   
D.\(\left\{ \begin{array}{l}x = 1 + t\\y = t\\z = 1 - t\end{array} \right..\)

A.\(\frac{1}{6}.\)      
B.\(\frac{3}{{20}}.\)    
C.\(\frac{2}{{15}}.\)      
D.\(\frac{1}{5}.\)

A.\(\frac{{2a}}{3}.\)    
B.\(\frac{{\sqrt 6 a}}{3}.\)  
C.\(\frac{{\sqrt 3 a}}{3}.\) 
D.\(\frac{a}{2}.\)

A.\(5.\)
B.\(4.\)
C.\(3.\)
D.\(2.\)

A.\(202.\)
B.\(203.\)
C.\(206.\)
D.\(207.\)

A.\(2.\)
B.\(3.\)
C.\(1.\)
D.\(0.\)

A.\(216\,\pi {a^3}.\)
B.\(150\pi {a^3}.\)
C.\(54\pi {a^3}.\)
D.\(108\pi {a^3}.\)