The true statement is
An endocrine gland is a cluster of hormone-secreting cells surrounded by a network of capillaries.
Endocrine glands are the glands of the endocrine system that secretes hormone directly into the blood such as pituitary gland, parathyroid gland, ovaries, testes etc.
The anterior pituitary gland is surrounded by a capillary network that extends from the hypothalamus and also the follicles of the thyroid gland produce hormones are released into the surrounding capillary network for transport to the rest of the body with the help of the circulatory system. Each parathyroid gland is covered by connective tissue and contains many secretory cells that are associated with a capillary network.
So it can be concluded from the above information that the endocrine glands are surrounded by network capillaries to transport the secreted hormone to the body.