How can you check the singleEmailMessage Limits in Lightning apex Before sending email using singleEmailMessage in Salesforce?

How can you check the singleEmailMessage Limits in Lightning apex Before sending email using singleEmailMessage object?

a.using Limits.getEmail(Limits());

b. using Messaging.reversingEmailcapacity();

c.using Limits.ReserveSingleEmailCapacity();

d.using Singleemailmessage.getLimits();