Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to introduce an older cat to a new dog [title] Start by keeping the animals apart. [step] When you're introducing a new dog to an older cat, you'll want to plan their introduction carefully. Though they're sharing your home, male sure that they're confined to their own spaces at first.

Ending1: If an older or older cat can fit in a new room, a new dog may prefer the smaller house or be less likely to feel stressed about missing them than an older or older cat. [substeps] Make sure the room you get them into feels like home. Ending2: Let them spend time in separate rooms or areas at first. Over time, gradually move into establishing a stronger bond with your new cat. Ending3: Allowing them time to adjust to each others' scents within your home will help them get used to each other. [substeps] You'll want to prevent any direct contact until your new dog has had his vet checkup and is cleared of any contagious diseases or infections. Ending4: When you do introduce two new dogs, keep the existing dogs separate and move all the cats away from each other. This provides enough time to establish a good environment and support the introduction.

Answer format: ending1/ending2/ending3/ending4