Which of the following would be beneficial for a low-birth-weight baby?

A) Being left alone except for basic care
B) Being touched and massaged
C) A simple sensory environment, to avoid overstimulation
D) A cool environment to reduce fluid loss from sweating

Low-birth-weight babies benefit from being touched and massaged. This can help with weight gain, muscle development, and brain function. The other options, such as being left alone, a simple sensory environment, or a cool environment, do not provide the necessary stimulation and support for a low-birth-weight baby's development and growth.