To solve the problem, we need to identify the pattern in the given series based on the provided arrangement:

S D 9 5 E # K 6 T I 8 P 1 % A 2 C λ L M U 3 W @ N 4 © J $ 7 F B

The series given is: #K5 P1I C λ A?

Let's break it down step by step:

1. Identify the positions of the elements in the series:

   • is at position 6

   • K is at position 7
   • 5 is at position 4
   • P is at position 12
   • 1 is at position 13
   • I is at position 10
   • C is at position 16
   • λ is at position 17
   • A is at position 14

2. Determine the pattern:

   • The first element (#) is at position 6.
   • The second element (K) is at position 7, which is 1 position after #.
   • The third element (5) is at position 4, which is 3 positions before K.
   • The fourth element (P) is at position 12, which is 8 positions after 5.
   • The fifth element (1) is at position 13, which is 1 position after P.
   • The sixth element (I) is at position 10, which is 3 positions before 1.
   • The seventh element (C) is at position 16, which is 6 positions after I.
   • The eighth element (λ) is at position 17, which is 1 position after C.
   • The ninth element (A) is at position 14, which is 3 positions before λ.

3. Following the pattern, the next element should be:

   • 6 positions after A (position 14).

Counting 6 positions after A (position 14):

• 15: 2
• 16: C
• 17: λ
• 18: L
• 19: M
• 20: U

Therefore, the element that should come in place of the question mark (?) is U.