#### Answer

The correct answer is B, C, D, E are meaningful, A,F are not

#### Work Step by Step

For an expression to have meaning, we can't have any operation that takes both a scalar and a vector as arguments.
Expression A takes the dot product of a scalar and a vector and so is not meaningful, expression B multiplies two scalars and so is meaningful, expression C multiplies two scalars and so is meaningful, expression D takes the dot product of two vectors and so is meaningful, expression E adds two scalars and so is meaningful, and expression F takes the dot product of a scalar and vector and so is not meaningful.
The correct answer is B, C, D, E are meaningful, A,F are not