Final answer:
The synaptic connectivity pattern in which many presynaptic neurons connect to a single postsynaptic neuron is known as convergence, which is integral for the summation of signals at the axon hillock.
Step-by-step explanation:
The pattern of synaptic connectivity where a large number of presynaptic neurons provide input to a single postsynaptic neuron is known as convergence. This scenario allows multiple signals from various inputs to be integrated at the axon hillock of the postsynaptic neuron. Here, excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) are summed, which determines if the threshold for an action potential is reached. Thus, option B) convergence is the correct answer for the described pattern of synaptic connectivity.