Let's watch for Myra Lane and Richard and Ben and Frances can be on the lookout for the others.

The correct placement of the commas is shown in this answer: b. Let’s watch for Myra, Lane, and Richard; and Ben and Frances can be on the lookout for the others.

Here are the following choices:

a. Let’s watch for Myra, Lane, and Richard, and Ben and Frances can be on the lookout for the others.

b. Let’s watch for Myra, Lane, and Richard; and Ben and Frances can be on the lookout for the others.

c. Let’s watch for Myra, Lane, and Richard, and: Ben and Frances can be on the lookout for the others.

d. Let’s watch for Myra, Lane, and Richard; and Ben, and Frances can be on the lookout for the others.

The correct placement of the commas is shown in this answer:

b. Let’s watch for Myra, Lane, and Richard; and Ben and Frances can be on the lookout for the others.

Explanation:

Use a comma before any coordinating conjunction (and, but, for, or, nor, so, yet) that links 2 freelance clauses ...

Use a comma when a subordinate clause that starts a sentence.

Use commas to offset appositives from the remainder of the sentence.