Instructions: In each of the following sentences, there is one word missing. Identify the missing word from the given choices. A number of clinical trials shown regular exercise to be strongly linked to heightened immunity.
Explanation: (A) এখানে Subject-verb agreement এর নিয়ম অনুযায়ী, "A number of clinical trials HAVE shown..." হবে। Clinical trials এর পর একটি Auxiliary Verb (have) missing আছে।