The Linear Model for Long-Term Trend Is $y = \beta _ { 0 } + \beta _ { 1 } t + \varepsilon$

The linear model for long-term trend is $y = \beta _ { 0 } + \beta _ { 1 } t + \varepsilon$ , where t is the time period. The trend is indicated by:

A) $\beta _ { 0 }$ .
B) $\beta _ { 1 }$ .
C) $y$ .
D) t .