Explanation
The best answer is A. Rightsizing.
Rightsizing is the process of restructuring a company so it can make a profit more efficiently and meet updated business objectives1. Organizations will usually rightsize their business by reducing their workforce, reorganizing upper management, cutting costs, and changing job roles2.
Rightsizing can help solve the issue of VMs constantly ballooning, while the memory usage of several other VMs is significantly lower than their resource allocation. Ballooning is a memory reclamation technique used when ESXi host runs out of memory. It involves a balloon driver that consumes unused memory within the VM's address space and makes it available for other uses by the host machine3. However, ballooning can also degrade the performance of the VMs and cause swapping or paging4.
By rightsizing the VMs, the systems administrator can adjust the memory allocation according to the actual demand and usage of each VM. This can prevent overprovisioning or underprovisioning of memory resources and improve the efficiency and profitability of the company. Rightsizing can also help avoid redundancies, streamline workflows, and make better hiring decisions1.