The veins of Lagerstroemia indica belong to

A, the epidermis is composed of a layer of closely arranged, colorless and transparent cells, which contain no chloroplasts, can't carry out photosynthesis and can't produce oxygen. A is wrong;

B, vein belongs to transport tissue, contains no chloroplast, can't carry out photosynthesis, does not produce oxygen, B error;

C, mesophyll cells near the upper epidermis are cylindrical, arranged neatly, and are palisade tissues. There are more chloroplasts, stronger photosynthesis and more oxygen released in palisade tissue. C is correct;

D. The mesophyll cells near the lower epidermis are irregular in shape and loosely arranged, which are sponge tissues, and the sponge tissues contain less chloroplasts.

So choose: C.