Dorsal-ventral patterning in the oocyte of Drosophila depends on the expression of Gurken. The following events occur during generation of dorsal-ventral polarity.

A. The oocyte nucleus travels to the anterior dorsal side of the oocyte where it localizes gurken mRNA.
B. Gurken protein reaches only those follicle cells closest to the oocyte nucleus.
C. The protein product forms an anterior-posterior gradient along dorsal surface of the oocyte.

What would happen if maternal deficiency of gurken occurs?

Correct option is D

EXPLANATION-
1. This is incorrect – Dorsal-ventral polarity does not occur properly in gurken deficiency.

2.  This is incorrect – Dorsalized follicle cells do not form; the absence of gurken prevents this.

3. This is incorrect – Absence of gurken does not lead to repression of pipe. In fact, pipe is expressed in the absence of gurken.

4.  This is correct – Ventralization of the embryo occurs due to uniform pipe expression.

So, the correct option is (d) Ventralization of the embryo would occur.