**Core Concept**
The sex ratio of children in the 0-6 age group is a demographic indicator used to assess the balance between male and female children in a population. It is an important measure of population health and well-being, as it can reflect factors such as maternal health, infant mortality, and access to healthcare.

**Why the Correct Answer is Right**
The correct sex ratio of children in the 0-6 age group according to the 2011 census is 914 girls per 1000 boys. This ratio is determined by analyzing the number of girls and boys in the population within this age group. The higher ratio of girls to boys in this age group suggests that there is a preference for male children, leading to a higher number of female foetuses being selectively aborted. This is a result of the son preference and the availability of ultrasound technology, which has led to a decline in the sex ratio at birth.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not reflect the actual sex ratio of children in the 0-6 age group according to the 2011 census.
* **Option B:** This option is incorrect because it is a lower ratio than the actual sex ratio, suggesting a higher number of male children, which is not reflective of the demographic trends in India.
* **Option C:** This option is incorrect because it is a higher ratio than the actual sex ratio, suggesting a higher number of female children, which is not reflective of the demographic trends in India.

**Clinical Pearl / High-Yield Fact**
The declining sex ratio at birth in India is a major public health concern, as it can lead to a shortage of women in the population, which can have significant social and economic implications.

**Correct Answer:** D. 914.