Which IQ range is called trainable IQ level of mentally retarded children?

Concept

In special education, children with intellectual disability are grouped by Intelligence Quotient (IQ) into broad educational categories. The classical scheme is: Educable (mild) at roughly IQ 50–70, who can manage basic academics; Trainable (moderate) at roughly IQ 35/36–49, who cannot handle formal academics but can be trained in self-care, daily-living and simple vocational skills; and Custodial (severe/profound) below about IQ 35, who need lifelong care.

Application

The question asks for the trainable level. By definition the trainable band sits between the educable band above it and the custodial band below it — i.e. the moderate range of about IQ 36 to 49. Among the offered ranges, 36–49 is exactly this moderate/trainable band.

Cross-check

50–69 falls in the educable (mild) band, so it is the schoolable level, not trainable; 70–79 is at or above the borderline-to-normal cut-off, not a disability category; 35 and below is the custodial (severe/profound) band that needs care rather than training. Only 36–49 names the trainable level.