Basic Complexity Analysis

Given two arrays $A$ and $B$ , both of size $n \geq 1$ , which of these three algorithms runs the slowest?

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Algorithm algo1(A,B)
   b ← A[0]
   for i ← 1 to n -1 do
      b ←  b + A[i]
   return b

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Algorithm  algo2(A,B)
   c ←  0
   for i ←  1 to n -1 do
     s ←  0
     for j ←  1 to n -1 do
        s ←  s + A[0]
        for k ←  1 to n -1  do
           if k % 1 = 0 then
              return s                     
           s ←  s + 9

   return c

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Algorithm  algo3(A,B)
   c ←  0
   for i ←  1 to n -1 do
     s ←  0
     for j ←  1 to n -1 do
        s ←  s + A[0]
        for k ←  1 to j do
           s ←  s + A[k]
        if B[i] = s then
           c ←  c + 1
   return c