Step-by-step explanation:
A. direct contact
Also known as juxtacrine signalling where cells in contact are next to each other. Here in this question plasmodesmata which acts as a channel through which molecules move in and out of nearby cells is an example of direct contact signalling.
B. endocrine signalling
In this signalling, signal is sent from one cell to other cells which is far away from the cell. The signal will be in a steady state. Insulin is secreted from Beta cells of pancreas to other target cells through blood. So, insulin secretion is an example for endocrine signalling.
C. synaptic signalling
The junction between nerve cells where transmission of signals is called synapse. And the paracrine signalling that occurs among the neuron cells can be specifically called as synaptic signalling.
D. paracrine signalling
If cells release signals and is passed to the local environment or immediate surrounding areas it is called paracrine signalling. The clue is itself in the question "cells on local environment only". So this histamine signalling to other cells follows paracrine signalling