Final answer:
At 12-15 months, a child typically cannot yet walk alone well. Infants at this stage can often stand and may begin to walk with support. By two years, children can engage in more advanced motor skills such as climbing stairs and handling small objects.
Step-by-step explanation:
At 12-15 months, a child is still developing various motor skills. Typically, at this stage, children may not be able to walk alone well (option b). However, infants around one year old can often stand while holding onto things and might begin to walk (as indicated in Figure 23.5.11). At around ten months, infants start to crawl and can sit unsupported. By 24 months, toddlers have advanced enough to walk, run, and climb stairs with assistance. Fine motor skills develop as children grow, allowing them to handle small objects and perform tasks such as putting raisins into a bottle, yet this is likely a skill more developed around the age of two. This would imply an infant at 12 months could potentially put raisins into a bottle but might lack the precision and coordination of older toddlers.