Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid gene
a. normally leads to formation of head structures.
b. normally leads to formation of tail structures.
c. is transcribed in the early embryo.
d. is a protein present in all head structures.

The product of the bicoid gene is a protein that is responsible for establishing the anterior-posterior axis during the embryogenesis phase of Drosophila development.
The bicoid protein is localized at the anterior end of the egg of the drosophila and the anterior end it represses the expression of the mRNAs that are translated at the posterior end and helps in the expression of only anterior genes due to which it plays an essential role in the formation of anterior structures and thus the head of the fruit fly.
Therefore, from the given question it is very clear that since the absence of anterior larval body parts occurs in the absence of bicoid mRNA, bicoid must be specifying the head structures.