Fill in the blanks with suitable Modals. Choose the correct option from below :

As my son is lagging behind in his studies he ________ attend the class regularly.

must

The best option to fill in the blank is:

Option 4: must

Here's why:

• The sentence expresses a strong necessity or obligation. The son's lagging studies suggest a clear need for regular attendance to improve.
• "Could" suggests possibility or ability, but not a strong requirement. It's too weak for this context.
• "Can" also indicates ability, but it doesn't emphasize the importance or urgency of attending class.
• "May" suggests permission, which isn't the right tone here. We want to convey the son's duty, not just his allowed choice.
• "Must" is the strongest modal, emphasizing the absolute necessity of attending class for the son's progress. It leaves no room for doubt or alternative options.