Answer:
Poison pill
Step-by-step explanation:
Poison pill is a strategy that is used to avoid that another party takes over an organization by allowing the current shareholders of the firm to acquire more shares. According to this, the answer is that a rights offer made to existing shareholders with the sole purpose of making it more difficult for another firm to acquire the company is called poison pill as this is a defensive strategy that companies use to avoid a takeover from an outside party.