Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to train a german shepherd [title] Begin your training attempts at around eight weeks old. [step] Although any german shepherd dog is trainable, they are very strong and powerful animals. If you start out with a puppy, you have the opportunity to shape and mold its personality and develop your relationship early.

Ending1: [substeps] If you start it as a puppy, begin training it quickly at around eight to 12 weeks old. Make sure you train your puppy at a safe pace. Ending2: [substeps] If you happen to get an older dog, adult dogs can still be trained effectively. German shepherds can be very protective of their family members, so you want to socialize your puppy early in puppyhood. Ending3: Early training is a great stepping stone to poor socialization. It also means recognizing that socialization is lacking. Ending4: Be very careful when training german shepherds if you haven't had any luck with them. [substeps] German shepherds have strong personalities and are generally gentle, affectionate, and generous.

Answer format: ending1/ending2/ending3/ending4