To solve the problem of decoding 'CLEAVE' using the given code language rules, let's first analyze the pattern used to encode 'BEAUTY' into 'DDZTVA' and 'GLORIA' into 'INNTHZ'. By understanding the transformation rules, we can apply the same pattern to 'CLEAVE'.

1. Analyze the encoding of 'BEAUTY' to 'DDZTVA':
   • \(B \rightarrow D\): The letter moves 2 steps forward in the alphabet.
   • \(E \rightarrow D\): The letter moves 1 step backward.
   • \(A \rightarrow Z\): The letter moves 1 step backward, considering the alphabet wraps around.
   • \(U \rightarrow T\): The letter moves 1 step backward.
   • \(T \rightarrow V\): The letter moves 2 steps forward.
   • \(Y \rightarrow A\): The letter moves 2 steps forward, considering the alphabet wraps around.
2. Analyze the encoding of 'GLORIA' to 'INNTHZ':
   • \(G \rightarrow I\): 2 steps forward.
   • \(L \rightarrow N\): 2 steps forward.
   • \(O \rightarrow N\): 1 step backward.
   • \(R \rightarrow T\): 2 steps forward.
   • \(I \rightarrow H\): 1 step backward.
   • \(A \rightarrow Z\): 1 step backward, considering the alphabet wraps around.
3. Determine the pattern:
   • Positions 1, 4 move 2 steps forward.
   • Positions 2, 5 move 2 steps forward or backward, whichever fits the pattern.
   • Positions 3, 6 move 1 step backward.
   • Wrap around the alphabet where necessary.
4. Apply the pattern to 'CLEAVE':
   • \(C (3) \rightarrow E (5)\): 2 steps forward.
   • \(L (12) \rightarrow N (14)\): 2 steps forward.
   • \(E (5) \rightarrow D (4)\): 1 step backward.
   • \(A (1) \rightarrow Z (26)\): 1 step backward, wrapping around.
   • \(V (22) \rightarrow X (24)\): 2 steps forward.
   • \(E (5) \rightarrow D (4)\): 1 step backward.
5. Thus, 'CLEAVE' is encoded as 'ENDZXD'.

Therefore, the correct answer is ENDZXD.